Add zend opcache template to enable it

Add zend opcache template to enable it. This template is based on the opcache.ini in the php54-php-pecl-zendopcache-7.0.2-4.el6.x86_64.
However, the name you chosen wasn't that bad. I liked the fact that it was very similar to APC. Though, I just think the above is bit more consistent.