tests/test-gendoc-ru.t

tests: fix test-update-branches to remove non-conflicting file

I was clearly very sloppy when I wrote the test case for
experimental.updatecheck=noconflict. The test case that checks that
one can move between commits with a removed file was deleting a file
that was modified between the source and target commits, which
resulted in a "change/delete" conflict. Since that is a conlict, the
update correctly failed. Let's fix the test by removing a file that is
not modified between the two commits.

#require docutils gettext

  $ $TESTDIR/check-gendoc ru
  checking for parse errors