google: drop duplicate path trim from opendir()

opendir() trims the path passed then calls getDriveFile() -
which immediately does the same trim operation. This breaks
opendir() on the root directory, which causes the failure of
the testStat() test when it checks the ctime of the root dir.

apps/files_external/lib/google.php

@@ -228,8 +228,6 @@ class Google extends \OC\Files\Storage\Common {
 	}
 
 	public function opendir($path) {
-		// Remove leading and trailing slashes
-		$path = trim($path, '/');
 		$folder = $this->getDriveFile($path);
 		if ($folder) {
 			$files = array();