[intro] Add cancel button to add dialog when needed

SparkleShare/SparkleIntro.cs

@@ -443,16 +443,31 @@ namespace SparkleShare {
 
 							};
 
+
+						if (StepTwoOnly) {
+
+							Button cancel_button = new Button (_("Cancel"));
+
+							cancel_button.Clicked += delegate {
+								Destroy ();
+							};
+
+							controls.Add (cancel_button);
+
+
+						} else {
+
 							Button skip_button = new Button (_("Skip"));
 
 							skip_button.Clicked += delegate {
 								ShowStepThree ();
 							};
 
-
-						if (!StepTwoOnly)
 							controls.Add (skip_button);
 
+						}
+
+
 						controls.Add (AddButton);
 
 					layout_vertical.PackStart (header, false, false, 0);