KFW: problems with non-interactive logons

KFW: problems with non-interactive logons

Non-interactive logons cause two problems:

(1) on XP/2003 the logon event handlers do not get triggered and on
    all platforms the LogonScript does not get executed.
    As a result, ccache files are not deleted.
(2) on all platforms, accessing the credential cache causes
    krbcc32s.exe to be spawned.  This process never terminates.

This patch tests for interactive logons.  If the logon is not
interactive, the Network Provider exits immediately.

ticket: new
component: windows
tags: pullup

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@19296 dc483132-0cff-0310-8789-dd5450dbe970