netinfo: Make get() use getLinks

By making get() use getLinks we avoid getLinks being called by nics
and by vlans, so it is all in all one less process creation and
less work to retrieve vlans and bridges as well.

For that to be possible we add the isBridge and isBond to ipwrapper.

Change-Id: Ia80df220cbf3d07fd229246748a0b0ebdcb302d2
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/21563
Reviewed-by: Dan Kenigsberg <danken@redhat.com>