nosql: set manage_package_repo to false on RH/CentOS

MongoDB repository provides packages that do not support systemd
correctly on RHEL & CentOS, so we switched to RHCL & EPEL to have RH
supported packages.

When using them, we have to modify the way to use puppetlabs-mongodb by
disabling manage_package_repo to have good parameters.

For Debian & Ubuntu, no change this we continue to pin mongodb packages
to have recent ones.

This patch is only updating the way to use mongodb module on RH/CentOS.

Signed-off-by: Emilien Macchi <emilien.macchi@enovance.com>
Merge pull request #591 from enovance/mongo-manage-repo

nosql: set manage_package_repo to false on RH/CentOS