manifest: Update gdm configure arguments
manifest: Update gdm configure arguments

Specifically we want --enable-systemd-journal.

See https://bugzilla.gnome.org/show_bug.cgi?id=676181

GNOME/gnome-ostree,chergert/gnome-continuous,djdeath/gnome-ostree,GNOME/gnome-ostree,GNOME/gnome-ostree,vrutkovs/vrutkovs.github.io,vrutkovs/vrutkovs.github.io,djdeath/gnome-ostree,chergert/gnome-continuous,vrutkovs/vrutkovs.github.io,djdeath/gnome-ostree,chergert/gnome-continuous