macros: Manage metadata.json file in puppet-lint jobs

Since puppet 3.x, Puppet Labs Forge accept only the metadata.json file
for module description (Modulefile is now deprecated). Our puppet-lint
jobs use the Modulefile to determine module name; this patch keep the «
retro-compat. » with Modulefile, but fetch the module name in
metadata.json file if available.

Change-Id: I1738ee14706d136837b2c8fe4ffa741907291bb8
Merge "macros: Manage metadata.json file in puppet-lint jobs"