pull: Write commitpartial files for local imports too
pull: Write commitpartial files for local imports too

Just like HTTP fetches, these can be interrupted, so we need to write
the commitpartial files.

Closes: #324
Approved by: yuqi-zhang

gatispaeglis/ostree,gatispaeglis/ostree,gatispaeglis/ostree,GNOME/ostree,GNOME/ostree,gatispaeglis/ostree,GNOME/ostree,gatispaeglis/ostree,GNOME/ostree,gatispaeglis/ostree,GNOME/ostree