Fix test failures.

I'm not sure where the dependency on 'six' comes froms (pytz, perhaps?).

And it looks like zc.buildout 1.5.2 changed its templates or something: witness
the BUILDOUT_ORIGINAL_PYTHONPATH changes, and the extra code in the generated
addsitepackages.  It's possible that my changes will break the tests if run
with zc.buildout 1.5.1.  If this happens, please yell at me, and I'll try to
come up with some ellipses to make them pass on both.

src/z3c/recipe/i18n/README.txt

@@ -219,8 +219,8 @@ The i18nextract.py contains the following code:
   import os
   path = sys.path[0]
   if os.environ.get('PYTHONPATH'):
-      os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ['PYTHONPATH']
       path = os.pathsep.join([path, os.environ['PYTHONPATH']])
+  os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ.get('PYTHONPATH', '')
   os.environ['PYTHONPATH'] = path
   import site # imports custom buildout-generated site.py
   import os
@@ -254,8 +254,8 @@ The i18nmergeall.py contains the following code:
   import os
   path = sys.path[0]
   if os.environ.get('PYTHONPATH'):
-      os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ['PYTHONPATH']
       path = os.pathsep.join([path, os.environ['PYTHONPATH']])
+  os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ.get('PYTHONPATH', '')
   os.environ['PYTHONPATH'] = path
   import site # imports custom buildout-generated site.py
   <BLANKLINE>
@@ -280,8 +280,8 @@ The i18nstats.py contains the following code:
   import os
   path = sys.path[0]
   if os.environ.get('PYTHONPATH'):
-      os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ['PYTHONPATH']
       path = os.pathsep.join([path, os.environ['PYTHONPATH']])
+  os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ.get('PYTHONPATH', '')
   os.environ['PYTHONPATH'] = path
   import site # imports custom buildout-generated site.py
   <BLANKLINE>
@@ -306,8 +306,8 @@ The i18ncompile.py contains the following code:
   import os
   path = sys.path[0]
   if os.environ.get('PYTHONPATH'):
-      os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ['PYTHONPATH']
       path = os.pathsep.join([path, os.environ['PYTHONPATH']])
+  os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ.get('PYTHONPATH', '')
   os.environ['PYTHONPATH'] = path
   import site # imports custom buildout-generated site.py
   <BLANKLINE>
@@ -387,8 +387,8 @@ The i18nextract.py contains the following code:
   import os
   path = sys.path[0]
   if os.environ.get('PYTHONPATH'):
-      os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ['PYTHONPATH']
       path = os.pathsep.join([path, os.environ['PYTHONPATH']])
+  os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ.get('PYTHONPATH', '')
   os.environ['PYTHONPATH'] = path
   import site # imports custom buildout-generated site.py
   import os
@@ -422,6 +422,7 @@ The site.py has inserted the extraPaths.
       """Add site packages, as determined by zc.buildout.
   <BLANKLINE>
       See original_addsitepackages, below, for the original version."""
+      ...
       buildout_paths = [
           ...
           '/sample-buildout/extra/path/1',
@@ -432,6 +433,7 @@ The site.py has inserted the extraPaths.
           if not sitedircase in known_paths and os.path.exists(sitedir):
               sys.path.append(sitedir)
               known_paths.add(sitedircase)
+      ...
       return known_paths
   <BLANKLINE>
   ...
@@ -452,8 +454,8 @@ The i18nmergeall.py contains the following code:
   import os
   path = sys.path[0]
   if os.environ.get('PYTHONPATH'):
-      os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ['PYTHONPATH']
       path = os.pathsep.join([path, os.environ['PYTHONPATH']])
+  os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ.get('PYTHONPATH', '')
   os.environ['PYTHONPATH'] = path
   import site # imports custom buildout-generated site.py
   <BLANKLINE>
@@ -478,8 +480,8 @@ The i18nstats.py contains the following code:
   import os
   path = sys.path[0]
   if os.environ.get('PYTHONPATH'):
-      os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ['PYTHONPATH']
       path = os.pathsep.join([path, os.environ['PYTHONPATH']])
+  os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ.get('PYTHONPATH', '')
   os.environ['PYTHONPATH'] = path
   import site # imports custom buildout-generated site.py
   <BLANKLINE>
@@ -573,8 +575,8 @@ The i18nextract.py contains the following code:
   import os
   path = sys.path[0]
   if os.environ.get('PYTHONPATH'):
-      os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ['PYTHONPATH']
       path = os.pathsep.join([path, os.environ['PYTHONPATH']])
+  os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ.get('PYTHONPATH', '')
   os.environ['PYTHONPATH'] = path
   import site # imports custom buildout-generated site.py
   import os
@@ -664,8 +666,8 @@ The i18nmergeall.py contains the following code:
   import os
   path = sys.path[0]
   if os.environ.get('PYTHONPATH'):
-      os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ['PYTHONPATH']
       path = os.pathsep.join([path, os.environ['PYTHONPATH']])
+  os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ.get('PYTHONPATH', '')
   os.environ['PYTHONPATH'] = path
   import site # imports custom buildout-generated site.py
   <BLANKLINE>
@@ -696,8 +698,8 @@ The i18nstats.py contains the following code:
   import os
   path = sys.path[0]
   if os.environ.get('PYTHONPATH'):
-      os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ['PYTHONPATH']
       path = os.pathsep.join([path, os.environ['PYTHONPATH']])
+  os.environ['BUILDOUT_ORIGINAL_PYTHONPATH'] = os.environ.get('PYTHONPATH', '')
   os.environ['PYTHONPATH'] = path
   import site # imports custom buildout-generated site.py
   <BLANKLINE>

src/z3c/recipe/i18n/tests.py

@@ -24,6 +24,7 @@ def setUp(test):
     zc.buildout.testing.install('ZConfig', test)
     zc.buildout.testing.install('ZODB3', test)
     zc.buildout.testing.install('pytz', test)
+    zc.buildout.testing.install('six', test)
     zc.buildout.testing.install('transaction', test)
     zc.buildout.testing.install('zc.lockfile', test)
     zc.buildout.testing.install('zc.recipe.egg', test)