Merge pull request #2149 from mattermost/plt-1949

PLT-1949 Fixing cacheing issue on IE for admin console

api/admin.go

@@ -120,6 +120,8 @@ func getConfig(c *Context, w http.ResponseWriter, r *http.Request) {
 	cfg := model.ConfigFromJson(strings.NewReader(json))
 	json = cfg.ToJson()
 
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	w.Header().Set("Expires", "0")
 	w.Write([]byte(json))
 }