Log Message:
Add php-opcache version 5.5.1 package.  This is part of official PHP 5.5.1
distribution.

php-opcache is the Zend OPcache module which provides faster PHP execution
through opcode caching and optimization.  It improves PHP performance by
storing precompiled script bytecode in the shared memory. This eliminates the
stages of reading code from the disk and compiling it on future access. In
addition, it applies a few bytecode optimization patterns that make code
execution faster.