manager: fix timed login

There was some confusion over multiple competing enabled variables.

This commit eliminates the confusion.

https://bugzilla.gnome.org/show_bug.cgi?id=680348
NEWS: update for release
configure: bump to 3.12.0
ConsoleKit: a pair of tweaks

It looks like there were a couple of breaks when porting away from
ck-connector.

The first issue is that consolekit uses some hard-coded rules to decide
if a given session is associated with the hard-coded 'Seat1' or not.
One of these rules is the "x11-display-device" property being set.  We
were setting the "display-device" property instead, which is not for
graphical sessions.  This was causing a new seat to be dynamically
created each time gdm started which was causing us to send
ActivateSession requests to the wrong seat.

The second issue is that ActivateSession will "fail" with "Session
already active" errors.  Ignore those.

https://bugzilla.gnome.org/show_bug.cgi?id=727072
pam: improve keyring integration on fedora

This commit properly hooks in gnome-keyring into the password
stack, so password changes are caught at login time, and the keyring
is appropriately rekeyed.
manager: don't require session to be on a seat

vnc sessions, for instance, aren't on a seat.
doap: update URLs