lib/clean.js: use single quotes

diff --git a/lib/clean.js b/lib/clean.js
index 719864d..caef19c 100644 (file)
--- a/lib/clean.js
+++ b/lib/clean.js
@@ -369,7 +369,7 @@ var CleanCSS = {
         .replace(/['"]/g, '');
 
       if (/^(http|https):\/\//.test(importedFile))
-        return "@import url(" + importedFile + ");";
+        return '@import url(' + importedFile + ');';
 
       var relativeTo = importedFile[0] == '/' ?
         options.root :