add memcache.so only for php 5.x
add memcache.so only for php 5.x

MDrollette/symfony1,onceit/symfony1,ngscz/symfony1,ngscz/symfony1,Recras/symfony1,onceit/symfony1,simoncast/symfony1,Recras/symfony1,rock-symphony/rock-symphony,simoncast/symfony1,onceit/symfony1,MDrollette/symfony1,ngscz/symfony1,MDrollette/symfony1,simoncast/symfony1,Recras/symfony1,rock-symphony/rock-symphony,rock-symphony/rock-symphony