fix for puppet >3.3 - /etc/init.d/mongodb init script

fix for puppet >3.3, to ensure that the default init script is replaced, it now spits a warning of 'Warning: /Stage[main]/Mongodb/File[/etc/init.d/mongodb]: Ensure set to :present but file type is link so no content will be synced' under >3.3 otherwise, and this module blats out its own init scripts