binary touch delays for poll_timeout before returning

[Jin Choi]

Using libmemcached 1.0.16 against a memcached 1.4.24 server, a memcached_touch() called using the binary protocol delays for MEMCACHED_BEHAVIOR_POLL_TIMEOUT milliseconds before returning. This is easily exhibited by using the utility executable memtouch:

memtouch --binary somekey 60

where "somekey" exists. Without the --binary flag, it returns instantly; with it, it takes 5 seconds.

Also, contrary to the documentation which claims the default for MEMCACHED_BEHAVIOR_POLL_TIMEOUT is -1, it is actually 5000 (set in defaults.h as MEMCACHED_DEFAULT_TIMEOUT).