Updated init.pp with simplified management of paths.

[pier4r]

Problem

   Error: /Stage[main]/Profiles::Base::Sysctl/Sysctl[vm.swappiness]/Exec[enforce-sysctl-value-vm.swappiness]/returns: change from notrun to 0 failed: Could not find command '/sbin/sysctl'

Solution

See changes

Testing

• CentOs 6.9 : works
• CentOs 7.4 : works
• Ubuntu 14.05 : works
• Ubuntu 16.04 : works.