Prefix database parameters with database_ for consistency

Although database configurations were moved to the new database
section, parameters were not renamed accordingly.

This change renames those parameter for consistency with the other
modules and actual database configuration names.

Conflicts:
  manifests/init.pp

Change-Id: I34855839963faa4c60f482df014b4986c7acab92
(cherry picked from commit 585a417fc99c1971823408fce25eb926faee268c)