Remove unused struct StatResponseCtx
Remove unused struct StatResponseCtx

Change-Id: I033f70c06cf6cfd8757f4749c3e518eaafd8c257
Reviewed-on: http://review.couchbase.org/96645
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine