inflight downstream conns count assert() fixed
inflight downstream conns count assert() fixed

Change-Id: I6b4a8e91e33bf2fa290731ac6316a32c7b09117e
Reviewed-on: http://review.membase.org/3719
Tested-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>
Reviewed-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>

membase/moxi,zbase/moxi,zbase/moxi,zbase/moxi,couchbase/moxi,zbase/moxi,membase/moxi,couchbase/moxi,membase/moxi,membase/moxi,couchbase/moxi,zbase/moxi,couchbase/moxi,couchbase/moxi,couchbase/moxi,membase/moxi,membase/moxi