Generate separate master-KDC and slave-KDC config files, with

Generate separate master-KDC and slave-KDC config files, with
different names for the database files.  (Slave config files unused as
yet.)  Ensure that the master-KDC environment is used when running
kadmin.local or kdb5_util.  Define and use a new proc for deleting all
KDC database and keytab files.

Set KPASSWD in default.exp.

Run kadmin, pwchange, pwhist, gssftp, telnet, v4gssftp tests only once each.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@21067 dc483132-0cff-0310-8789-dd5450dbe970