tests/test-xdg.t

py3: use "%d" % val for int rather than pycompat.bytestr

Earlier I used pycompat.bytestr() to convert integers to bytes, but we can do
b"%d" % val to convert that int to bytes. b'' is already added by the
transformer.

Thanks to Yuya for suggesting this.

#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