tests: fix vcs Hg helper functions get_user_name and get_user_email to actually use provided config_file

Running just test_get_user_name and test_get_user_email would fail when run as:
  py.test kallithea/tests/vcs/test_repository.py -k test_get_user

The config file was not used at all, and the tests would only pass when
test_get_config_value had been run first and as an unfortunate side-effect had
read the same file.

kallithea/lib/vcs/backends/hg/repository.py

@@ -613,7 +613,7 b' class MercurialRepository(BaseRepository'
         :param config_file: A path to file which should be used to retrieve
           configuration from (might also be a list of file paths)
         """
-        username = self.get_config_value('ui', 'username')
+        username = self.get_config_value('ui', 'username', config_file=config_file)
         if username:
             return author_name(username)
         return None
@@ -625,7 +625,7 b' class MercurialRepository(BaseRepository'
         :param config_file: A path to file which should be used to retrieve
           configuration from (might also be a list of file paths)
         """
-        username = self.get_config_value('ui', 'username')
+        username = self.get_config_value('ui', 'username', config_file=config_file)
         if username:
             return author_email(username)
         return None