Bug 736574 - PageInfo: Fix an if-condition causing a failure to sort the media by count. r=Dao

browser/base/content/pageinfo/pageInfo.js

@@ -187,7 +187,7 @@ gImageView.onPageMediaSort = function(columnname) {
   var treecol = tree.columns.getNamedColumn(columnname);
 
   var comparator;
-  if (treecol.index == COL_IMAGE_SIZE) {
+  if (treecol.index == COL_IMAGE_SIZE || treecol.index == COL_IMAGE_COUNT) {
     comparator = function numComparator(a, b) { return a - b; };
   } else {
     comparator = function textComparator(a, b) { return a.toLowerCase().localeCompare(b.toLowerCase()); };