CP-18257: Add pool_update.pool_apply
CP-18257: Add pool_update.pool_apply

Signed-off-by: Cheng Zhang <f157832f2f1df5a7c962d3abb092f6b1ea020882@citrix.com>

Frezzle/xen-api,srowe/xen-api,thomassa/xen-api,thomassa/xen-api,srowe/xen-api,Frezzle/xen-api,euanh/xen-api,euanh/xen-api,Frezzle/xen-api,srowe/xen-api,euanh/xen-api,thomassa/xen-api,thomassa/xen-api,euanh/xen-api,thomassa/xen-api,euanh/xen-api,Frezzle/xen-api,thomassa/xen-api,srowe/xen-api,srowe/xen-api,Frezzle/xen-api,euanh/xen-api