GSimpleAsyncResult is deprecated in favor of the simpler GTask, so use
that instead. This cuts down on the deprecation warnings.
I wanted to do both separately, but porting one without the other led to
some faulty casts from GSimpleAsyncResult to GTask (and vice versa).
* This is necessary because sometimes we don't want to complain,
for expected errors, when running nested operations.
* The fact that we have to do this is silly, and soon there
will be a solution in glib itself.
https://bugzilla.gnome.org/show_bug.cgi?id=688165
* Death by a thousand paper cuts from gir and vapi not liking
the fact that the secret.h file was not usable uninstalled
and installed in the same way.
