Merge pull request #1704 from jarlebring/upnp_caps

Fix capitalization in HTTP-header in SOAP request (fixes #1696)

internal/upnp/upnp.go

@@ -454,7 +454,7 @@ func soapRequest(url, service, function, message string) ([]byte, error) {
 	}
 	req.Header.Set("Content-Type", `text/xml; charset="utf-8"`)
 	req.Header.Set("User-Agent", "syncthing/1.0")
-	req.Header.Set("SOAPAction", fmt.Sprintf(`"%s#%s"`, service, function))
+	req.Header["SOAPAction"] = []string{fmt.Sprintf(`"%s#%s"`, service, function)} // Enforce capitalization in header-entry for sensitive routers. See issue #1696
 	req.Header.Set("Connection", "Close")
 	req.Header.Set("Cache-Control", "no-cache")
 	req.Header.Set("Pragma", "no-cache")