Deprecation - Use puppet stacktrace if available
Deprecation - Use puppet stacktrace if available

A previous PR (#685) was raised on this issue, however once it was merged it was discovered that Puppet 3 with future parser enabled was calling the Puppet 4 version of the deprecation function. The Puppet stacktrace is not available until Puppet 4.6, so this was breaking existing setups. The solution was to check is the stacktrace was defined, and if it was to use it as part of the message output.

DavidS/puppetlabs-stdlib,fuel-infra/puppetlabs-stdlib,jbondpdx/puppetlabs-stdlib,puppetlabs/puppetlabs-stdlib,HelenCampbell/puppetlabs-stdlib