pull up r19296 from trunk

pull up r19296 from trunk

 r19296@cathode-dark-space:  jaltman | 2007-03-28 14:03:45 -0400
 ticket: new
 subject: KFW: problems with non-interactive logons
 component: windows
 tags: pullup

 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: 5493
version_fixed: 1.6.1

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-6@19340 dc483132-0cff-0310-8789-dd5450dbe970