This is to prevent suricata-update from being installed if it
would otherwise be installed based on in being bundled, and
its dependencies being available.
Warn the user that Suricata-Update will not be installed if it
is bundled, but python-yaml is missing (this will also cover
the case where Python is missing).
Add "Install suricata-update" to the build summary. For consistency,
relable "Suricatasc install" as "Install suricatasc".