Fix getRawPathInfo for the '/' edge case

lib/private/request.php

@@ -165,8 +165,12 @@ class OC_Request {
 		if (strpos($path_info, $name) === 0) {
 			$path_info = substr($path_info, strlen($name));
 		}
+		if($path_info === '/'){
+			return '';
+		} else {
 			return $path_info;
 		}
+	}
 
 	/**
 	 * @brief Check if this is a no-cache request