packaging: setup: check access rights on storage

during customization also check for access permissions
on storage location avoiding to fail storage domain
creation in a later stage.

Change-Id: I5c97ee7a8b98d0f41a906dd9507ace88d44da38d
Bug-Url:https://bugzilla.redhat.com/999865
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>