Show current open file & connection limits when we hit then.
Show current open file & connection limits when we hit then.

Make it easier to diagnose when we hit these limits - include the
current and maximum values in the log messages (if possible).

Change-Id: I75451d016cd38019831efe6429d31172c32d17d6
Reviewed-on: http://review.couchbase.org/38557
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

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