Merge pull request matplotlib#2132 from mdboom/font_cache_fix

Attempt to fix Travis tests by not using font cache there.

Author: mdboom

lib/matplotlib/font_manager.py

@@ -1324,12 +1324,15 @@ def findfont(prop, fontext='ttf'):
         return result
 
 else:
-    cachedir = get_cachedir()
-    if cachedir is not None:
-        if sys.version_info[0] >= 3:
-            _fmcache = os.path.join(cachedir, 'fontList.py3k.cache')
-        else:
-            _fmcache = os.path.join(cachedir, 'fontList.cache')
+    if not 'TRAVIS' in os.environ:
+        cachedir = get_cachedir()
+        if cachedir is not None:
+            if sys.version_info[0] >= 3:
+                _fmcache = os.path.join(cachedir, 'fontList.py3k.cache')
+            else:
+                _fmcache = os.path.join(cachedir, 'fontList.cache')
+    else:
+        _fmcache = None
 
     fontManager = None