MB-22145: Add missing cookie lock from EPStoreEvictionTest:MB_21976
MB-22145: Add missing cookie lock from EPStoreEvictionTest:MB_21976

The EPStoreEvictionTest:MB_21976 test changes the status of the cookie
to ENGINE_E2BIG so we can determine if notify is called (which will
change the status to ENGINE_NOT_MY_VBUCKET).

Changing the status of the cookie must be done with the cookie lock
held.

Change-Id: Ic809807ff8dd56ec644cab9c0777470bcf9ce894
Reviewed-on: http://review.couchbase.org/71456
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>

couchbase/ep-engine,daverigby/ep-engine,daverigby/ep-engine,membase/ep-engine,daverigby/ep-engine,daverigby/ep-engine,couchbase/ep-engine,couchbase/ep-engine,daverigby/kv_engine,membase/ep-engine,membase/ep-engine,daverigby/kv_engine,membase/ep-engine,daverigby/kv_engine,couchbase/ep-engine,daverigby/kv_engine