Allow keystone_config hide config values from Puppet logs

Hide configuration value from Puppet logs if the secret parameter
is set to true.

Fixes: bug #1279329
Change-Id: If045df6f167c94592db85848872d4de512a3d758
Merge "Allow keystone_config hide config values from Puppet logs"
Merge git://github.com/puppetlabs/puppetlabs-keystone