Fix for tabix sources with non-VCF payloads.
Fix for tabix sources with non-VCF payloads.

Traksewt/dalliance,limeng12/dalliance,jeffhsu3/dalliance,ENCODE-DCC/dalliance,bartcharbon/dalliance,ENCODE-DCC/dalliance,dasmoth/dalliance,warelab/dalliance,jeffhsu3/dalliance,dasmoth/dalliance,limeng12/dalliance,bartcharbon/dalliance,Traksewt/dalliance,warelab/dalliance