sp: invalidate lvm cache if attachSD fails

Change-Id: I9f740d9048aabbfaecba55cff338c57f31a20801
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=883390
Signed-off-by: Yeela Kaplan <ykaplan@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/13221
Reviewed-by: Ayal Baron <abaron@redhat.com>
Reviewed-by: Federico Simoncelli <fsimonce@redhat.com>