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
<?php 
var_dump(ini_get( 'memcache.hash_function')); // crc32
var_dump(ini_get( 'memcache.hash_strategy')); // crc32, it shoud be standard
var_dump(ini_set( 'memcache.hash_strategy', 'consistent' )); // false,if success shoud be return the old value
var_dump(ini_get( 'memcache.hash_strategy'));    // consistent, it's right now
var_dump(ini_set( 'memcache.hash_function', 'crc32' ));    // false,if success shoud be return the old value
var_dump(ini_get( 'memcache.hash_function'));  // crc32, set the memcache.hash_function
var_dump(ini_get( 'memcache.hash_strategy'));  // crc32, the hash_strategy is overrided by the memcache.hash_function

?>