http: remove BUG_ON(1) statement

Remove BUG_ON(1) statement that was a leftover from debugging.

Bug #1189 https://redmine.openinfosecfoundation.org/issues/1189
Bug #1212 https://redmine.openinfosecfoundation.org/issues/1212

Prscript:
- PR build: https://buildbot.suricata-ids.org/builders/inliniac/builds/328
- PR pcaps: https://buildbot.suricata-ids.org/builders/inliniac-pcap/builds/243