criticals: g_object_unref called on objects with only floating references

These warnings were present before the recent static analysis fixes.

Steps to reproduce

• Run G_ENABLE_DIAGNOSTIC=1 xfburn
• Exit xfburn

Output

(xfburn:273433): GLib-GObject-CRITICAL **: A floating object GstPadTemplate 0x7ca597211e20 was finalized. This means that someone
called g_object_unref() on an object that had only a floating
reference; the initial floating reference is not owned by anyone
and must be removed with g_object_ref_sink().

(xfburn:273433): GLib-GObject-CRITICAL **: A floating object GstPadTemplate 0x7ca597211ef0 was finalized. This means that someone
called g_object_unref() on an object that had only a floating
reference; the initial floating reference is not owned by anyone
and must be removed with g_object_ref_sink().

(xfburn:273433): GLib-GObject-CRITICAL **: A floating object GstPadTemplate 0x7ca597212090 was finalized. This means that someone
called g_object_unref() on an object that had only a floating
reference; the initial floating reference is not owned by anyone
and must be removed with g_object_ref_sink().

(xfburn:273433): GLib-GObject-CRITICAL **: A floating object GstPipeline 0x7d35972550f0 was finalized. This means that someone
called g_object_unref() on an object that had only a floating
reference; the initial floating reference is not owned by anyone
and must be removed with g_object_ref_sink().

(xfburn:273433): GLib-GObject-CRITICAL **: A floating object GstPipeline 0x7d35972580f0 was finalized. This means that someone
called g_object_unref() on an object that had only a floating
reference; the initial floating reference is not owned by anyone
and must be removed with g_object_ref_sink().

Version info

1072a40a compiled on Arch Linux