Small fixes to make loading of logs faster

Removes filtering of log types where not necessary, removes filtering based on namespace when filtering based on repository (superfluous check that was causing issues in MySQL preventing the use of the correct index) and fix some other small issues around the API

Fixes https://jira.coreos.com/browse/QUAY-931

data/model/log.py

@@ -26,7 +26,7 @@ def _logs_query(selections, start_time, end_time, performer=None, repository=Non
   if performer:
     joined = joined.where(LogEntry.performer == performer)
 
-  if namespace:
+  if namespace and not repository:
     namespace_user = user.get_user_or_org(namespace)
     if namespace_user is None:
       raise DataModelException('Invalid namespace requested')