remote-modify: Clear cached summaries when the remote is modified.
remote-modify: Clear cached summaries when the remote is modified.

This fixed some issues in the test where changing the url cause the
cache:ing to fail to update due to the mtimes being to new in combination
with the HTTP If-Modified-Since use.

flatpak/flatpak,flatpak/flatpak,flatpak/flatpak,flatpak/flatpak,flatpak/flatpak