tests/test-xdg.t

py3: don’t subscript socket.error

On Python 2, socket.error was subscriptable. On Python 3, socket.error is an
alias to OSError and is not subscriptable. The except block passes the
exception to self.send_error(). This fails on both Python 2 (if it was
executed) and Python 3, as it expects a string.

Getting the attribute .strerror works on Python 2 and Python 3, and has the
same effect as the previous code on Python 2.

#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