Added the route action for disabling the root user in the extensions.
Modified the resource extension to allow the generation of a DELETE
route on the resource itself.
Implemented root-disable on the mysql guest. Added not implemented
error messages for all other datastores.
Change-Id: I52519b86c47694c554b624d1d2fbe7a001af55fc
Partially implements: blueprint root-disable
Depends-On: I27831eb361c2b219a9623f152b9def73a2865d67
2a5439aad2