MB-16910: Stop logging multiple 'warmup is complete' messages
MB-16910: Stop logging multiple 'warmup is complete' messages

Fix prevents logging more than one 'Engine warmup is complete' message
for each bucket. Fix resolves problem of overloading log file with the
message mentioned above.

Change-Id: Icfdeb5def6e3f055159e1a57430c6dc661382e30
Reviewed-on: http://review.couchbase.org/58898
Reviewed-by: abhinav dangeti <d73ef2279de6577f7bf081737ee47554bbb7dc82@couchbase.com>
Reviewed-by: Manu Dhundi <158873d90a7ef40f3637a222b7329c09d0222554@couchbase.com>
Reviewed-by: Chiyoung Seo <fcffc23db27b19ee4ebba46695ee6b50e09216a2@couchbase.com>
Tested-by: Chiyoung Seo <fcffc23db27b19ee4ebba46695ee6b50e09216a2@couchbase.com>

hisundar/ep-engine,couchbase/ep-engine,membase/ep-engine,daverigby/kv_engine,hisundar/ep-engine,hisundar/ep-engine,membase/ep-engine,teligent-ru/ep-engine,teligent-ru/ep-engine,membase/ep-engine,teligent-ru/ep-engine,couchbase/ep-engine,owendCB/ep-engine,daverigby/ep-engine,hisundar/ep-engine,daverigby/ep-engine,daverigby/kv_engine,daverigby/kv_engine,teligent-ru/ep-engine,owendCB/ep-engine,membase/ep-engine,daverigby/ep-engine,couchbase/ep-engine,owendCB/ep-engine,daverigby/kv_engine,daverigby/ep-engine,couchbase/ep-engine,owendCB/ep-engine