Amendment: Don't try to absolutize urls if already absolute

Author: Michael-Herzog

src/Libraries/SmartStore.Core/WebHelper.cs

@@ -640,7 +640,7 @@ public static string GetAbsoluteUrl(string url, HttpRequestBase request)
 				return url;
 			}
 
-			if (url.Contains("://"))
+			if (url.Contains("://") || url.StartsWith("//"))
 			{
 				return url;
 			}