Let setup.py compile_catalog process all language files

Two years ago the translation files have been split into several
files, separating the log messages of different log levels from each
other, like X.pot, X-log-warning.pot, X-log-info.pot, and so on.
However, the setup.py command `compile_catalogs`, that comes from the
babel package and compiles the corresponding .po files into .mo
files, only supported one file per python package.  This means that
during packaging `compile_catalogs` never compiled the X-log-*.po
files, so the corresponding translations were always missing.

Since babel 2.3 the domain can be set to a space separated list of
domains.  This change adds the the additional log level files to the
domain list.

The obsolete check that .po and .pot files are valid is removed from
tox.ini.

Change-Id: I0d9cb16ac50caae570c57a1db6bed656bf13c3dc
Closes-Bug: #1536226

setup.cfg

@@ -217,7 +217,7 @@ tag_svn_revision = 0
 
 [compile_catalog]
 directory = nova/locale
-domain = nova
+domain = nova nova-log-critical nova-log-error nova-log-info nova-log-warning
 
 [update_catalog]
 domain = nova

tox.ini

@@ -27,9 +27,6 @@ basepython = python2.7
 deps = hacking
 commands =
   bash tools/flake8wrap.sh {posargs}
-  # Check that .po and .pot files are valid.
-  bash -c "find nova -type f -regex '.*\.pot?' -print0| \
-           xargs -0 -n 1 msgfmt --check-format -o /dev/null"
 
 [testenv:py34]
 # NOTE(mriedem): If py34 fails with "db type could not be determined", delete