Fixed support for Redis::SERIALIZER_IGBINARY for HHVM compability.
Fixed support for Redis::SERIALIZER_IGBINARY for HHVM compability.

This fixes failing tests and functionality against HVVM with current master and previous versions.

robocoder/cache,Ocramius/cache,Rican7/cache,Tobion/cache,anonpain/cache,jenniferyien/cache,mpdude/cache,piwik/cache,doktorsitesi/cache,jeskew/cache,doktorsitesi/cache,doctrine/cache,robocoder/cache,guilhermeblanco/cache