MB-10137 Initialize max_purged_seq field of compaction_ctx to zero
MB-10137 Initialize max_purged_seq field of compaction_ctx to zero

There exists an ambiguity about zero initialization of builtin
types for data members of POD types. Added an explicit statement
to set max_purged_seq to zero.

Change-Id: I5be9d158fd08c72715326e8dc454497ba83cae7f
Reviewed-on: http://review.couchbase.org/33785
Reviewed-by: Aaron Miller <41fcc51335f382e0855796cc35dd33f571f2d8f7@ninjawhale.com>
Reviewed-by: Ketaki Gangal <c7141f0717da6f2e739c31892f081a1a527a34e4@gmail.com>
Tested-by: Ketaki Gangal <c7141f0717da6f2e739c31892f081a1a527a34e4@gmail.com>

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