Revert "fetcher: Always open tmpfiles in repo location"

[cgwalters]

This reverts commit f7f6f87.

This seems to have broken flatpak, so we'll revert and then investigate.

Closes: #2900

[travier]

Looks like this is failing on something unrelated:

../src/switchroot/ostree-prepare-root.c:329:22: error: 'struct lcfs_mount_options_s' has no member named 'expected_digest'
  329 |           cfs_options.expected_digest = composefs_digest;
      |                      ^

[dustymabe]

The CI failure:

[2023-06-26T10:19:13.292Z] --- FAIL: ext.config.root-reprovision.luks.autosave-xfs (681.51s)

[2023-06-26T10:19:13.292Z]         harness.go:1741: mach.Start() failed: machine "f92f8bb4-6451-476a-8e55-f56772f90de2" failed to start: ssh journalctl failed: time limit exceeded

Is an instance of coreos/fedora-coreos-tracker#1511

I'll restart it.

[dbnicholson]

lcfs_mount_options_s

I believe this should be fixed by #2903.

[dbnicholson]

I rebased this to get the fix from #2903.