Perf: Skip logging DEBUG event if debug disabled
Perf: Skip logging DEBUG event if debug disabled

In update_event() we log (at DEBUG level) what the event has been
changed to. This occurs very frequently (on every command received),
and has a reasonable high cost as we create a SyslogEvent (see
logger_log_wrapper) for every log() call; even if the severity of the
event is ultimately not logged to a file.

Change-Id: I1e048666a6f8454902b2173cbe9a8abedc1f9d00
Reviewed-on: http://review.couchbase.org/52368
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>

couchbase/memcached,daverigby/memcached,daverigby/memcached,owendCB/memcached,cloudrain21/memcached-1,couchbase/memcached,couchbase/memcached,cloudrain21/memcached-1,cloudrain21/memcached-1,daverigby/kv_engine,daverigby/kv_engine,owendCB/memcached,daverigby/kv_engine,daverigby/memcached,owendCB/memcached,daverigby/memcached,couchbase/memcached,cloudrain21/memcached-1,daverigby/kv_engine,owendCB/memcached