* gssftp.exp: Invocation of ftpd changed to use -U /dev/null and

* gssftp.exp: Invocation of ftpd changed to use -U /dev/null and
-a so that the test may successfully be run by root without failing
(i.e. root is granted ftp access) and without opening the running
ftpd to a password attack (i.e. authorization is required).
Check for successful login messages added.

* v4gssftp.exp: Same changes.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@13304 dc483132-0cff-0310-8789-dd5450dbe970