Hi Megan,
I am able to build Windows 2012r2 Sysprep AMI packer v1.5.6 after adding use_proxy=false and passing ansible_winrm_server_cert_validation=ignore in the extra arguments.
Sorry I caught up with getting completed with the current project but I was able to continue to work with the debug version you saved me, which is not available anymore as you want me that the travis ci repo must be gone now.
Anyway, I am able to build Windows AMI in packer 1.5.6.
Grooooov and awesome!!!
John.