Fix runs with RabbitMQ >= 3.7.9

[alexconrey]

Pull Request (PR) description

RabbitMQ >= 3.7.9 rabbitmqctl exec produces table/column header output which does not parse cleanly with the current way that the module is setup. This implements a version check, which will update the command in the event a version with the --no-table-headers flag should be used.

This Pull Request (PR) fixes the following issues

Fixes #740

[wyardley]

The spec tests still will need to be adjusted, and there are some rubocop errors as well

[bastelfreak]

Hi @alexconrey, thanks for the PR. Can you please take a look at the failed spec tests?

[gokuatkai]

puppet: 4.7.1
puppet agent: 1.7.2
ruby (embedded): ruby 2.1.9p490
rabbitmq module version: 8.2.0

The variable @format_table_headers works inside the parent provider class Puppet::Provider::Rabbitmqctl. But when it runs the rabbitmq_user provider the variable is empty, would you know why?
I checked the change log of puppet versions and I did not see any fix regarding any scope for variable between inherited providers class.

[bastelfreak]

We need to do a modulesync here and afterwards rebase this branch.

[wyardley]

Hi @alexconrey: Looks like #759 should resolve this once approved / merged.