default_engine: Fix DEBUG_REFCNT macro
default_engine: Fix DEBUG_REFCNT macro

Change-Id: I5b9de60993f49d50cd3fb514eb68a410c69d447f
Reviewed-on: http://review.couchbase.org/44713
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

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