edit-glance-manage-command-for-recreate-db

As per https://bugs.launchpad.net/glance/+bug/1213197, and subsequent
review at https://review.openstack.org/#/c/47161/ Glance-manage commands
are proposed to be subcommands of 'db'. This would require change to the
script to recreate_db which calls the db_sync command.

Implements blueprint edit-glance-manage-command-for-recreate-db
Change-Id: I9470709ec34896dba7a37fdff4791206bb5ef5ed
Merge "edit-glance-manage-command-for-recreate-db"