Don't block when kinit_pkinit() fails
Installation of ipa-client with PKINIT authentication can block when
there is a problem with PKINIT, e.g. KDC does not accept the cert or the
anchor chain is incomplete. `kinit` falls back to password
authentication and asks the user to enter a password.
`kinit` does not have an option to force non-interactive mode. Sending
`\n` to stdin seems to be the only solution here.
Fixes: https://pagure.io/freeipa/issue/9333
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>