WorkspacesView: set the actual geometry when creating workspaces

If we created a workspace after showing the view, we would never
set the geometry on it, which would cause an exception in the
window layout code and leave the DND state tracking in an undefined
state.

https://bugzilla.gnome.org/show_bug.cgi?id=699029

js/ui/workspacesView.js

@@ -297,6 +297,8 @@ const WorkspacesView = new Lang.Class({
         if (newNumWorkspaces > oldNumWorkspaces) {
             for (let w = oldNumWorkspaces; w < newNumWorkspaces; w++) {
                 this._workspaces[w].setFullGeometry(this._fullGeometry);
+                if (this._actualGeometry)
+                    this._workspaces[w].setActualGeometry(this._actualGeometry);
                 this.actor.add_actor(this._workspaces[w].actor);
             }