* Set AGENT_TOOLSDIRECTORY in packer template
This was set in the ruby installer but it is referenced elsewhere so I
believe it makes the most sense to have this set centrally in the packer
template to be referenced across multiple scripts.
* Fix typo
* Capitalize env var in ws2016 template for consistency
* Set AGENT_TOOLSDIRECTORY in Initialize-VM.ps1
* Add missing env var for AGENT_TOOLSDIRECTORY in step in ws2016 template
Ryan Spletzer