Revert "syncrepo: Properly clean up .~tmp~ dirs"

This reverts commit 75f9ca3c.

This should be fixed in rsync versions newer than 3.2.3. In Arch the fix
has been shipped in the rsync 3.2.3-4 package, which our own mirrors now
have been updated to.

[1] https://github.com/WayneD/rsync/issues/192