Fix login password expiration detection with OTP

The preexisting code would execute two steps. First, it would perform a kinit.
If the kinit failed, it would attempt to bind using the same credentials to
determine if the password were expired. While this method is fairly ugly, it
mostly worked in the past.

However, with OTP this breaks. This is because the OTP code is consumed by
the kinit step. But because the password is expired, the kinit step fails.
When the bind is executed, the OTP token is already consumed, so bind fails.
This causes all password expirations to be reported as invalid credentials.

After discussion with MIT, the best way to handle this case with the standard
tools is to set LC_ALL=C and check the output from the command. This
eliminates the bind step altogether. The end result is that OTP works and
all password failures are more performant.

https://fedorahosted.org/freeipa/ticket/4412

Reviewed-By: Petr Vobornik <pvoborni@redhat.com>

ipalib/errors.py

@@ -584,6 +584,12 @@ class InvalidSessionPassword(SessionError):
     errno = 1201
     format= _('Principal %(principal)s cannot be authenticated: %(message)s')
 
+class PasswordExpired(InvalidSessionPassword):
+    """
+    **1202** Raised when we cannot obtain a TGT for a principal because the password is expired.
+    """
+    errno = 1202
+
 ##############################################################################
 # 2000 - 2999: Authorization errors
 class AuthorizationError(PublicError):