shadow: set correct entries for pseudo terminals in /etc/securetty

shadow: set correct entries for pseudo terminals in /etc/securetty

In

commit 10cdd66fe800cffe3f2cbf5c95550b4f7902a311
Author: Ming Liu <ming.liu@windriver.com>
Date:   Thu Jul 18 10:04:22 2013 +0800

    libpam: add a new 'nullok_secure' option support to pam_unix

'null_ok_secure' option was fixed. Since that commit 'su' stopped working in
pseudo terminals (created in X environments) for root-accounts with empty
password.

Background: The PAM configuration for 'su' includes 'common-auth' which uses
'nullok_secure' option for pam_unix.

(From OE-Core rev: d28eba07553020bf9bfb1419663c1d18ab36ab66)

Signed-off-by: Andreas Müller <schnitzeltony@googlemail.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>