Fix reference leak in process_get_command()
Fix reference leak in process_get_command()

If a command-aborting error (invalid key, out of memory) was encountered
while processing a get command with multiple keys, the references to the
items before the one that caused the error were never being released.

emcconville/memcached,emcconville/memcached,emcconville/memcached,emcconville/memcached