[Building Sakai] Changes to KerberosUserDirectoryProvider and startup

[Seth Theriault]

Hello,

The code changes required to make KerberosUserDirectoryProvider
halt Sakai's startup if the provider is "improperly configured"
are noted here:

http://jira.sakaiproject.org/browse/SAK-16816

They have now been committed to trunk (future 2.7):

http://source.sakaiproject.org/viewsvn?view=rev&revision=68806

In addition, the documentation has been brought up to date:

http://source.sakaiproject.org/viewsvn?view=rev&revision=68807

These changes affect a specific, non-default situation in which a
KDC is being used as a directory and anyone with a valid Kerberos
principal is allowed to log into Sakai without a "local" account.

Anyone using the Kerberos provider in this way should review this
change.

Matthew Buckett of Oxford contributed the original 2.5 patch upon
which this work is based.

Seth