1.6.1dev: correct wrong email.errors module name

git-svn-id: http://trac.edgewall.org/intertrac/log:/branches/1.6-stable@17822 af82e41b-90c4-0310-8c96-b1721e28e2e2

trac/util/__init__.py

@@ -856,7 +856,7 @@ def has_resource(dist, module, resource_name):
                     if any('.'.join(names[:n + 1]) in provides
                            for n in range(len(names))):
                         return True
-                except (IOError, email.Errors.MessageError):
+                except (IOError, email.errors.MessageError):
                     pass
             toplevel = resource_name.split('/')[0]
             if dist.has_metadata('top_level.txt'):