repo: Really ignore progress changed user data
repo: Really ignore progress changed user data

The documentation says this is ignored, implying that you should pass
NULL to it. However, the function immediately returns in this case even
though the argument isn't used anywhere.

Closes: #458
Approved by: cgwalters

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