xtrabackup: handle missing facts gracefully

[fraenki]

Summary

When setting up a new server (or when reinstalling an existing server) with xtrabackup enabled, the Puppet Run may fail:

Error: Could not retrieve catalog from remote server: Error 500 on SERVER: Server Error: Evaluation Error:
Error while evaluating a Function Call, 'versioncmp' parameter 'a' expects a String value, got Undef
(file: /etc/puppetlabs/code/environments/development/modules/mysql/manifests/backup/xtrabackup.pp, line: 53, column: 8) on node

This patch adds a check to verify that the facts are available, before accessing them.

Additional Context

none

Related Issues (if any)

none

Checklist

• 🟢 Spec tests.
• 🟢 Acceptance tests.
• Manually verified. (For example puppet apply)

[fraenki]

rebased

[bronachfalls]

Closing and reopening this PR to rerun tests

[bronachfalls]

Hi @fraenki could you please rebase this? Thanks!

[bronachfalls]

Hi @fraenki , due to inactivity I am going to close this PR. If at any point you would like for it to be reopened, please let me know and I'll happily do so.

[fraenki]

@bronachfalls rebased; please reopen/merge

[bronachfalls]

@fraenki because this was rebased, I cannot reopen this specific PR. Would you be able to make your changes again and open a new PR?