Make MappedLocal::isLocal() true like for Local

Missed in 788c8540aa

lib/private/files/storage/mappedlocal.php

@@ -352,6 +352,13 @@ class MappedLocal extends \OC\Files\Storage\Common {
 		return $this->mapper->logicToPhysical($fullPath, true);
 	}
 
+	/**
+	 * {@inheritdoc}
+	 */
+	public function isLocal() {
+		return true;
+	}
+
 	/**
 	 * @param string $path
 	 * @return string