fix(dav): respect storage scheme when discovering token endpoint

exchangeRefreshToken hardcoded https:// for OCM discovery, breaking
federated shares against http remotes (e.g. integration test setup).
Use $this->secure to pick the scheme.

Signed-off-by: Micke Nordin <kano@sunet.se>

Author: mickenordin

lib/private/Files/Storage/DAV.php

@@ -265,7 +265,7 @@ protected function init(): void {
 	 */
 	protected function exchangeRefreshToken(): string {
 		try {
-			$host = 'https://' . $this->host;
+			$host = ($this->secure ? 'https://' : 'http://') . $this->host;
 			$ocmProvider = $this->discoveryService->discover($host);
 			$tokenEndpoint = $ocmProvider->getTokenEndPoint();