libnetwork: use plugin Content-Type headers v1.2

The MediaType was changed twice in;

- b3b7eb2723461b1eb4be692f4bced0ae8ea9cb58 ("application/vnd.docker.plugins.v1+json"   -> "application/vnd.docker.plugins.v1.1+json")
- 54587d861d6664d6d32bc62a46c0c7ea0c7853e6 ("application/vnd.docker.plugins.v1.1+json" -> "application/vnd.docker.plugins.v1.2+json")

But the (integration) tests were still using the old version, so let's
use the VersionMimeType const that's defined, and use the updated version.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

integration/plugin/graphdriver/external_test.go

@@ -126,7 +126,7 @@ func setupPlugin(t *testing.T, ec map[string]*graphEventsCounter, ext string, mu
 	}
 
 	respond := func(w http.ResponseWriter, data interface{}) {
-		w.Header().Set("Content-Type", "application/vnd.docker.plugins.v1+json")
+		w.Header().Set("Content-Type", plugins.VersionMimetype)
 		switch t := data.(type) {
 		case error:
 			fmt.Fprintf(w, "{\"Err\": %q}\n", t.Error())

libnetwork/drivers/remote/driver_test.go

@@ -66,7 +66,7 @@ func setupPlugin(t *testing.T, name string, mux *http.ServeMux) func() {
 	}
 
 	mux.HandleFunc("/Plugin.Activate", func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/vnd.docker.plugins.v1+json")
+		w.Header().Set("Content-Type", plugins.VersionMimetype)
 		fmt.Fprintf(w, `{"Implements": ["%s"]}`, driverapi.NetworkPluginEndpointType)
 	})
 

libnetwork/ipams/remote/remote_test.go

@@ -61,7 +61,7 @@ func setupPlugin(t *testing.T, name string, mux *http.ServeMux) func() {
 	}
 
 	mux.HandleFunc("/Plugin.Activate", func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/vnd.docker.plugins.v1+json")
+		w.Header().Set("Content-Type", plugins.VersionMimetype)
 		fmt.Fprintf(w, `{"Implements": ["%s"]}`, ipamapi.PluginEndpointType)
 	})
 

libnetwork/libnetwork_test.go

@@ -1164,7 +1164,7 @@ func TestInvalidRemoteDriver(t *testing.T) {
 	defer server.Close()
 
 	mux.HandleFunc("/Plugin.Activate", func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/vnd.docker.plugins.v1+json")
+		w.Header().Set("Content-Type", plugins.VersionMimetype)
 		fmt.Fprintln(w, `{"Implements": ["InvalidDriver"]}`)
 	})
 
@@ -1207,19 +1207,19 @@ func TestValidRemoteDriver(t *testing.T) {
 	defer server.Close()
 
 	mux.HandleFunc("/Plugin.Activate", func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/vnd.docker.plugins.v1+json")
+		w.Header().Set("Content-Type", plugins.VersionMimetype)
 		fmt.Fprintf(w, `{"Implements": ["%s"]}`, driverapi.NetworkPluginEndpointType)
 	})
 	mux.HandleFunc(fmt.Sprintf("/%s.GetCapabilities", driverapi.NetworkPluginEndpointType), func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/vnd.docker.plugins.v1+json")
+		w.Header().Set("Content-Type", plugins.VersionMimetype)
 		fmt.Fprintf(w, `{"Scope":"local"}`)
 	})
 	mux.HandleFunc(fmt.Sprintf("/%s.CreateNetwork", driverapi.NetworkPluginEndpointType), func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/vnd.docker.plugins.v1+json")
+		w.Header().Set("Content-Type", plugins.VersionMimetype)
 		fmt.Fprintf(w, "null")
 	})
 	mux.HandleFunc(fmt.Sprintf("/%s.DeleteNetwork", driverapi.NetworkPluginEndpointType), func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/vnd.docker.plugins.v1+json")
+		w.Header().Set("Content-Type", plugins.VersionMimetype)
 		fmt.Fprintf(w, "null")
 	})