Added support for CentOS 6.x package names

In CentOS and RHEL 6.x, php53* packages have been renamed to php* to reflect the fact that versions of php prior to 5.3 are not supported and 5.3 is the official version of Cent and RH 6.

I have changed the package references to include this update so that the php cookbook works on CentOS and RHEL 6.x