Fix memory leak in imlib_list_fonts()

Spotted by Sebastien Ballet.

src/lib/font_load.c

@@ -469,12 +469,11 @@ __imlib_font_list_fonts(int *num_ret)
                                     list = malloc(sizeof(char *));
                                  list[l - 1] = strdup(dir[j]);
                               }
-                            free(dir[j]);
                          }
                     }
                   free(path);
                }
-             free(dir);
+             __imlib_FileFreeDirList(dir, d);
           }
      }
    *num_ret = l;