core: Changed attach storage cmd & params to support add without activate

Changed the AttachStorageDomainToPoolCommand and it's corresponding
parameters to support attaching a storage domain to a pool without attempting
to activate the domain

Change-Id: Id3d96b95ba2ca6f63623f89433741c2509ec3c0e
Related-To: https://bugzilla.redhat.com/1096971
Signed-off-by: Tal Nisan <tnisan@redhat.com>