Call update-ca-certificates on startup of hub xmlrpc container

[nadvornik]

What does this PR change?

Call update-ca-certificates on startup of hub xmlrpc container.
Without this change the service does not see the certificates mounted in /etc/pki/trust/anchors volume.

GUI diff

No difference.

• DONE

Documentation

• No documentation needed: bugfix
• DONE

Test coverage

TBD

• DONE

Links

uyuni-project/uyuni-tools#292

• DONE

Changelogs

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[cbosdo]

Please add a changelog too.