Prior to ticket 7892 it would use the default host/ principal
when no principal was given on the command line.
ticket: 7892
# Test kinit and klist with client keytab defaults.
realm.extract_keytab(realm.user_princ, realm.client_keytab);
+realm.run([kinit, '-k', '-i'])
+realm.klist(realm.user_princ)
+realm.run([kdestroy])
realm.kinit(realm.user_princ, flags=['-k', '-i'])
realm.klist(realm.user_princ)
out = realm.run([klist, '-k', '-i'])