cursor: Fix incorrect comment

Since this code was written, mutter is now again responsible for
setting up the default root cursor.

https://bugzilla.gnome.org/show_bug.cgi?id=708465
smartcard: Fix run-time warning

Don't unref a destroyed GTask

https://bugzilla.gnome.org/show_bug.cgi?id=708536
power: Add a test with a failing mouse battery

With help from Martin Pitt <martinpitt@gnome.org>

https://bugzilla.gnome.org/show_bug.cgi?id=708199
3.10.0