vendor: Replace github.com/jackpal/gateway with github.com/calmh/gateway (fixes #3142)

Switch to my forked version which contains a fix for this issue. I'll
track upstream in the future if things update there, and attempt to
contribute back fixes...

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3149

vendor/manifest

@@ -19,6 +19,13 @@
 			"revision": "3c0690cca16228b97741327b1b6781397afbdb24",
 			"branch": "master"
 		},
+		{
+			"importpath": "github.com/calmh/gateway",
+			"repository": "https://github.com/calmh/gateway",
+			"revision": "edad739645120eeb82866bc1901d3317b57909b1",
+			"branch": "master",
+			"notests": true
+		},
 		{
 			"importpath": "github.com/calmh/luhn",
 			"repository": "https://github.com/calmh/luhn",
@@ -49,12 +56,6 @@
 			"revision": "5f1c01d9f64b941dd9582c638279d046eda6ca31",
 			"branch": "master"
 		},
-		{
-			"importpath": "github.com/jackpal/gateway",
-			"repository": "https://github.com/jackpal/gateway",
-			"revision": "32194371ec3f370166ee10a5ee079206532fdd74",
-			"branch": "master"
-		},
 		{
 			"importpath": "github.com/juju/ratelimit",
 			"repository": "https://github.com/juju/ratelimit",