Revert "install golang 1.11 on appveyor machines"

This reverts commit 2af4f4d.

appveyor.yml

@@ -16,55 +16,8 @@ environment:
 clone_folder: c:\gopath\src\github.com\hashicorp\packer
 
 install:
-  - ps: |
-        # Installs golang on Windows.
-        #
-        # # Run script:
-        # .\install-go.ps1
-        #
-        # # Download and run script:
-        # $env:GOVERSION = '1.5.3'
-        # iex ((new-object net.webclient).DownloadString('SCRIPT_URL_HERE'))
-
-        $version = '1.11'
-
-        $downloadDir = $env:TEMP
-        $packageName = 'golang'
-        $url32 = 'https://storage.googleapis.com/golang/go' + $version + '.windows-386.zip'
-        $url64 = 'https://storage.googleapis.com/golang/go' + $version + '.windows-amd64.zip'
-        $goroot = "C:\go$version"
-
-        # Determine type of system
-        if ($ENV:PROCESSOR_ARCHITECTURE -eq "AMD64") {
-          $url = $url64
-        } else {
-          $url = $url32
-        }
-
-        if (Test-Path "$goroot\bin\go") {
-          Write-Host "Go is installed to $goroot"
-          exit
-        }
-
-        echo "Downloading $url"
-        $zip = "$downloadDir\golang-$version.zip"
-        if (!(Test-Path "$zip")) {
-          $downloader = new-object System.Net.WebClient
-          $downloader.DownloadFile($url, $zip)
-        }
-
-        echo "Extracting $zip to $goroot"
-        if (Test-Path "$downloadDir\go") {
-          rm -Force -Recurse -Path "$downloadDir\go"
-        }
-        Add-Type -AssemblyName System.IO.Compression.FileSystem
-        [System.IO.Compression.ZipFile]::ExtractToDirectory("$zip", $downloadDir)
-        mv "$downloadDir\go" $goroot
   - set GO15VENDOREXPERIMENT=1
-  - set GOROOT=C:\go1.11
-  - set Path=%GOROOT%\bin;%PATH%
   - echo %Path%
-  - echo %GOROOT%
   - go version
   - go env
   - go get github.com/mitchellh/gox