mod/ssl: Add option to configure SSL mutex

[daenney]

This allows the end user to explicitly define or override what the SSLMutex or Mutex configuration for Apache will be as the platform default might not always be desirable.

Supersedes #1346
Closes #1346

[daenney]

@bmjen @igalic This change introduces a huge problem. Because we need to do a versioncmp for Debian all tests now fail as apache_version isn't set by any of the tests. What to do?

[bmjen]

This line is causing the lint failure:

metadata-json-lint metadata.json manifests/params.pp - WARNING: top-scope variable being used without an explicit namespace on line 216

[bmjen]

Thanks @daenney ! This looks good. Just need to fix the linting error.

[daenney]

@bmjen But that's a problem. Because apache_version comes from version.pp which gets loaded and exposed by init.pp as $apache_version = $::apache::version::default in the parameter declaration. But since params.pp gets loaded as part of init.pp, loading it in params.pp from version.pp might cause us to use a different version for the comparison there than anything the user might explicitly provide by passing in apache_version, breaking the configuration for their platform.

We get a circular dependency of sorts.

[bmjen]

Yep. I agree. I'm thinking you're right @daenney, in going back to the implementation of #1346... but with the correct parameter name, docs, and tests.

[daenney]

@bmjen Alright, updated. I used _ssl_mutex instead of the ssl_mutex_real pattern so we get the benefit of it being a private variable on Puppet 4.

[bmjen]

👍

[daenney]

🍻 💃 👯 🎉