Revert "Revert "MB-8581 Continue warmup after loading access_log.""

This reverts commit b74fdcc82e895d36f974e8e5ac3554532a3cdb90.

Conflicts:
	src/couch-kvstore/couch-kvstore.cc

Change-Id: If7aae2ee894911038410eee82aa6ec5a1474fbc0
Reviewed-on: http://review.couchbase.org/28152
Tested-by: Bin Cui <bin.cui@gmail.com>
Reviewed-by: Chiyoung Seo <chiyoung.seo@gmail.com>
Tested-by: Chiyoung Seo <chiyoung.seo@gmail.com>