wireguard: assume /32 or /128 if no CIDR is given

This brings the route_allowed_ips option into parity with the addresses
option, which makes these same assumption. The parsing selection is made
to be identical between these two settings.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

net/wireguard/files/wireguard.sh

@@ -82,9 +82,15 @@ proto_wireguard_setup_peer() {
         *:*/*)
           proto_add_ipv6_route "${allowed_ip%%/*}" "${allowed_ip##*/}"
         ;;
-        */*)
+        *.*/*)
           proto_add_ipv4_route "${allowed_ip%%/*}" "${allowed_ip##*/}"
         ;;
+        *:*)
+          proto_add_ipv6_route "${allowed_ip%%/*}" "128"
+        ;;
+        *.*)
+          proto_add_ipv4_route "${allowed_ip%%/*}" "32"
+        ;;
       esac
     done
   fi