synch up with a change from the trunk (Bug #203261)

mail/base/content/messageWindow.js

@@ -304,7 +304,7 @@ function delayedOnLoadMessageWindow()
 		if (window.arguments[1])
 			gCurrentFolderUri = window.arguments[1];
 		else
-      gCurrentFolderUri = folder ? folder.folderURL : null;
+      gCurrentFolderUri = folder ? folder.URI : null;
 
     if (window.arguments[2])
       originalView = window.arguments[2];