tests/test-xdg.t

delta-find: assume the target-rev if not specified

This will be useful in the next patch, but I am putting it in its own commit to
make sure we can easily bisect any subtle side effect. (none are expected, but
still)

#if no-windows no-osx

  $ mkdir -p xdgconf/hg
  $ echo '[ui]' > xdgconf/hg/hgrc
  $ echo 'username = foobar' >> xdgconf/hg/hgrc
  $ XDG_CONFIG_HOME="`pwd`/xdgconf" ; export XDG_CONFIG_HOME
  $ unset HGRCPATH
  $ hg config ui.username 2>/dev/null
  foobar

#endif