Refactor: Update internals in stats_context to operate on Cookie
Refactor: Update internals in stats_context to operate on Cookie

Change-Id: I78fe138abfd4ffa7103d676a93e4697753fde7b1
Reviewed-on: http://review.couchbase.org/85332
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