pimd: Fix leaked fd

When caling pim_sock_open if the failure cause happens, however
unlikely, don't leak the fd on failure.

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

pimd/pim_pim.c

@@ -371,6 +371,7 @@ static int pim_sock_open(struct in_addr ifaddr, int ifindex)
     return -1;
 
   if (pim_socket_join(fd, qpim_all_pim_routers_addr, ifaddr, ifindex)) {
+    close(fd);
     return -2;
   }