Fix converting Guzzle error codes in s2s storage

apps/files_sharing/lib/external/storage.php

@@ -248,9 +248,10 @@ class Storage extends DAV implements ISharedStorage {
 
 		// TODO: DI
 		$client = \OC::$server->getHTTPClientService()->newClient();
+		try {
 			$response = $client->post($url, ['body' => ['password' => $password]]);
-
-		switch ($response->getStatusCode()) {
+		} catch (\GuzzleHttp\Exception\RequestException $e) {
+			switch ($e->getCode()) {
 				case 401:
 				case 403:
 					throw new ForbiddenException();
@@ -259,6 +260,8 @@ class Storage extends DAV implements ISharedStorage {
 				case 500:
 					throw new \Exception();
 			}
+			throw $e;
+		}
 
 		return json_decode($response->getBody(), true);
 	}