Add fetching_user_source config option

Launchpad manages many information related to OpenStack at this
time, but the query takes much time for the processor. In addition,
stackalytics can be useful for OSS which are not managed with the
launchpad. So this patch adds a config option fetching_source so
that users can select fetching source. The default option is
'launchpad', so this patch doesn't affect at all on the default
option.

Change-Id: I4b7db745c36545e8897132cf6ccbb1c3fd6f3c07

stackalytics/processor/config.py

@@ -54,6 +54,9 @@ PROCESSOR_OPTS = [
                default='https://git.openstack.org/cgit/openstack/i18n/'
                        'plain/tools/zanata/translation_team.yaml',
                help='URI of translation team data'),
+    cfg.StrOpt("fetching-user-source", default='launchpad',
+               choices=['launchpad', '<None>'],
+               help="Source for fetching user profiles"),
     cfg.IntOpt('members-look-ahead', default=250,
                help='How many member profiles to look ahead after the last'),
     cfg.IntOpt('read-timeout', default=120,