Remove redundant field.

Change-Id: I783b3e029d7b176cd45a9c7cc887a79e63461d78
Bump srusers to pick up improve username casing handling.

This adds optional arguments for being case-insensitive without
modifying the defaults.

Change-Id: I6febb268ce2d4d157b8d4e3914bfa4c7c7d3e53a
Have the AuthHelper be case-insensitive on usernames.

If the underlying ldap is intending to be case-sensitive, this will
still be picked up by the password bind check. This change does,
however, allow a case-insensitive ldap (such as ours) to let users
login with any casing of username.

Change-Id: Ibb82133759cec7fc36cf9847e371584240ee4c88