Remove __main__ code from ipalib.x509 and ipalib.pkcs10
This code was presumably once used for testing, but has been
subsumed by the actual test suite.
Part of: https://fedorahosted.org/freeipa/ticket/6398
Reviewed-By: Jan Cholasta <jcholast@redhat.com>
Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>