Print storage command at DEBUG level
Print storage command at DEBUG level

Print the storage command (ADD,SET,REPLACE,CAS) for a storage
operation at DEBUG level. Note most other commands are printed
already.

Change-Id: Id137b2a81a0b5c344583f615990591730a9a592a
Reviewed-on: http://review.couchbase.org/53680
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

daverigby/memcached,daverigby/kv_engine,daverigby/memcached,daverigby/memcached,owendCB/memcached,couchbase/memcached,daverigby/memcached,couchbase/memcached,owendCB/memcached,owendCB/memcached,daverigby/kv_engine,daverigby/kv_engine,couchbase/memcached,couchbase/memcached,owendCB/memcached,daverigby/kv_engine