repo: Clean up temporaries after a transaction completes
repo: Clean up temporaries after a transaction completes

Prevously, we were just leaving temporary files there forever if
a transaction was interrupted.

https://bugzilla.gnome.org/show_bug.cgi?id=706344

resin-io/ostree,resin-io/ostree,GNOME/ostree,leandrosansilva/ostree,GNOME/ostree,resin-io/ostree,GNOME/ostree,sujitfulse/ostree,GNOME/ostree,gatispaeglis/ostree,leandrosansilva/ostree,leandrosansilva/ostree,gatispaeglis/ostree,resin-io/ostree,GNOME/ostree,resin-io/ostree,leandrosansilva/ostree,sujitfulse/ostree,leandrosansilva/ostree,sujitfulse/ostree,sujitfulse/ostree,gatispaeglis/ostree,gatispaeglis/ostree,gatispaeglis/ostree,sujitfulse/ostree,gatispaeglis/ostree