bgpd: Ensure that struct prefix_rd rd is zero'ed out

We are passing around the created rd, Just make sure that
the data is zero'ed out.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

bgpd/bgp_mplsvpn.c

@@ -109,7 +109,7 @@ int bgp_nlri_parse_vpn(struct peer *peer, struct attr *attr,
 	uint16_t type;
 	struct rd_as rd_as;
 	struct rd_ip rd_ip;
-	struct prefix_rd prd;
+	struct prefix_rd prd = {0};
 	mpls_label_t label = {0};
 	afi_t afi;
 	safi_t safi;