Add at signed for Puppet 3.2

This commit adds @ signs to the variables
evaluated in erb that are resolved from Puppet's
scope where the templates are compiled.

This is in response to deprecation warnings from
Puppet 3.2.

These changes should be backwards compatible to 2.7.x.

Change-Id: Ib85d863b00086f9f9cd0968347bd26d5d7481298