Fix {-y} template calculation for custom (TMS) tile grids

Previously, {-y} only worked for the standard web mercator tile grid. Now
a tile grid with an extent is required (which we get from
ol.tilegrid.createXYZ() anyway), and then the y calculation for TMS style
tile grids works as expected.

src/ol/source/xyzsource.js

@@ -87,7 +87,7 @@ ol.source.XYZ.prototype.getUrls = function() {
  */
 ol.source.XYZ.prototype.setUrl = function(url) {
   this.setTileUrlFunction(ol.TileUrlFunction.createFromTemplates(
-      ol.TileUrlFunction.expandUrl(url)));
+      ol.TileUrlFunction.expandUrl(url), this.tileGrid));
   this.urls_ = [url];
 };
 
@@ -97,6 +97,7 @@ ol.source.XYZ.prototype.setUrl = function(url) {
  * @param {Array.<string>} urls URLs.
  */
 ol.source.XYZ.prototype.setUrls = function(urls) {
-  this.setTileUrlFunction(ol.TileUrlFunction.createFromTemplates(urls));
+  this.setTileUrlFunction(
+      ol.TileUrlFunction.createFromTemplates(urls, this.tileGrid));
   this.urls_ = urls;
 };