examples: gtksink: call gst::deinit()

Needed so we can use the leaks tracer.

examples/src/bin/gtksink.rs

@@ -151,8 +151,15 @@ fn main() {
     gst::init().unwrap();
     gtk::init().unwrap();
 
+    {
         let app = gtk::Application::new(None, gio::ApplicationFlags::FLAGS_NONE);
 
         app.connect_activate(create_ui);
         app.run();
     }
+
+    // Optional, can be used to detect leaks using the leaks tracer
+    unsafe {
+        gst::deinit();
+    }
+}