Fixes empty session with non-empty current_user
Fixes empty session with non-empty current_user

Clear out session the first thing on invalid csrf token.

euank/moebooru-thin,moebooru/moebooru,moebooru/moebooru,nanaya/moebooru,moebooru/moebooru,moebooru/moebooru,euank/moebooru-thin,euank/moebooru-thin,nanaya/moebooru,nanaya/moebooru,moebooru/moebooru,euank/moebooru-thin,nanaya/moebooru,nanaya/moebooru,euank/moebooru-thin