Removing unused filter code. AuthenticationFilter was getting user object from DB and performing license operations with it.

Since we do not have license in Go anymore, this filter check is obsolete. Cleaning up this filter will prevent an un-necessary database call to load User object.
Merge remote-tracking branch 'upstream/master' into filter-clean-up-1
Enclosing debug logs with isDebugEnabled to prevent String object construction when unnecessary.
Merge pull request #213 from sachinsudheendra/filter-clean-up-1

Removing unused filter code...