openssh: fix login fails for ssh -o Batchmode=yes with empty passwords

openssh: fix login fails for ssh -o Batchmode=yes with empty passwords

The patch fixes the login fails for ssh -o Batchmode=yes when passwords is
empty and without authorized_keys file even if set "PermitEmptyPasswords yes"
in sshd_config file.

Here, to fix this issue, we remove the file auth2-none.c-avoid-authenticate-
empty-passwords-to-m.patch, that fixed broken pipe while sshd with pam,
but it isn't needed any more now, because we make it has gone by change
ChallengeResponseAuthentication value in sshd_config file.

(From OE-Core rev: f879a7406d8fce37e8baf5fe724d7ed0042d57f8)

Signed-off-by: Wenlin Kang <wenlin.kang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>