facebook/hhvm — pull request #3465 by porsihe (2014-08-14 09:47:27+00:00)
Title: set memcache's option use ini_set has some error

1. when use init_set('memcache.hash_function', $funciton_value ) will override the memcache.hash_strategy's value
2. cause 1's problem,when inited the thread, the memcache.hash_function's value will also override the memcache.hash_strategy's value;
3. when use init_set a option's value, if success the update_callback return true, then ini_set will return the option's old value, otherwise init_set will return false;

//use the code to test,like