pimd: crash while finding primary address.

RCA:
Trying to get primary address for the interface.
Unnumbered interface pick address from vrf device for non default.
While doing so it ends up in recursion without exit condition if vrf dev doesnt have any address.

Solution:
Break the recursion by checking if it is vrf device.

Signed-off-by: Saravanan K <saravanank@vmware.com>

pimd/pim_iface.c

@@ -894,8 +894,10 @@ struct in_addr pim_find_primary_addr(struct interface *ifp)
 	 * So let's grab the loopbacks v4 address
 	 * and use that as the primary address
 	 */
-	if (!v4_addrs && v6_addrs && !if_is_loopback(ifp)) {
+	if (!v4_addrs && v6_addrs && !if_is_loopback(ifp) &&
+	    !pim_if_is_vrf_device(ifp)) {
 		struct interface *lo_ifp;
+
 		// DBS - Come back and check here
 		if (ifp->vrf_id == VRF_DEFAULT)
 			lo_ifp = if_lookup_by_name("lo", vrf->vrf_id);