restapi: rsdl_metadata - quota.id in add disk

rsdl_metadata.yaml: added 'quota.id' to add/update disk
(to expose through ovirt-sdk/cli)

Change-Id: Icaa61142227e8751ee1b4444e7c71fcd5bf3415e
Bug-Url: https://bugzilla.redhat.com/1111150
Signed-off-by: Daniel Erez <derez@redhat.com>