Drop evil exception swallowing form removeNic

Change-Id: Ib7e2ef5e75a4637110843e205753cef1110de8ea
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/20179
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>