MB-30020 Set error context in MCBP validators
MB-30020 Set error context in MCBP validators

Set error context on request cookie upon failure of  additional checks
performed in mcbp command validators.

Change-Id: I49c4a4ad83e771299646ebe4d080ecaf46849ed8
Reviewed-on: http://review.couchbase.org/98720
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>

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