`ktutil` is a REPL-style utility that can be controlled only interactively.
The common approach of sending commands to stdin does not work with it on
systems where `readline` library has version less then 8.0 due to a bug
in that version.
With `pexpect` we avoid this bug because it emulates the terminal
when interacting with spawned process instead of simply sending all input
to stdin.
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Sergey Orlov
1b25270686