Chocolatey has been pretty flaky, so let's not rely on it.
Closes #43985
# - set PATH=%PATH%;%CD% -- this already happens above for sccache
# Install InnoSetup to get `iscc` used to produce installers
- - appveyor-retry choco install -y InnoSetup
+ - appveyor-retry appveyor DownloadFile https://s3.amazonaws.com/rust-lang-ci/rust-ci-mirror/2017-08-22-is.exe
+ - 2017-08-22-is.exe /VERYSILENT /SUPPRESSMSGBOXES /NORESTART /SP-
- set PATH="C:\Program Files (x86)\Inno Setup 5";%PATH%
# Help debug some handle issues on AppVeyor