Now that git_terminal_prompt can cleanly interact with /dev/tty on
Solaris, enable HAVE_DEV_TTY so that this code path is used for
credential reading instead of relying on the crippled getpass().
Signed-off-by: Ben Walton <bwalton@artsci.utoronto.ca> Signed-off-by: Junio C Hamano <gitster@pobox.com>