autobuilder: Look up latest snapshot in queueResolve
autobuilder: Look up latest snapshot in queueResolve

Otherwise we crash trying to find some arbitrary old version.  This
broke when we reworked the autobuilder's task stuff.

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