layout: Change setDummyCursorPosition to also set the size

If we are being used to follow a text entry cursor we also need to set
the size so that the popup menu avoids covering it.

https://bugzilla.gnome.org/show_bug.cgi?id=727579

js/ui/ibusCandidatePopup.js

@@ -155,7 +155,7 @@ const CandidatePopup = new Lang.Class({
 
         panelService.connect('set-cursor-location',
                              Lang.bind(this, function(ps, x, y, w, h) {
-                                 Main.layoutManager.setDummyCursorPosition(x, y);
+                                 Main.layoutManager.setDummyCursorGeometry(x, y, w, h);
                                  if (this._boxPointer.actor.visible)
                                      this._boxPointer.setPosition(Main.layoutManager.dummyCursor, 0);
                              }));