Use beta version of zendopcache for PHP < 5.5.
Use beta version of zendopcache for PHP < 5.5.

Fixes #1069.

datachand/lithium,davidpersson/lithium,UnionOfRAD/lithium,wbeater/lithium,davidpersson/lithium,jails/lithium,graphis/lithium,pixelcog/lithium,muyehub/lithium,graphis/lithium,pixelcog/lithium,m4rcsch/lithium-core-library,m4rcsch/lithium-core-library,muyehub/lithium,wbeater/lithium,UnionOfRAD/lithium,jails/lithium,whowgames/lithium,whowgames/lithium,datachand/lithium