leaving checkout only

Author: nvarscar

build/build_prep.ps1

@@ -3,9 +3,5 @@ dotnet tool install Cake.Tool --version 1.1.0
 Invoke-WebRequest https://cakebuild.net/download/bootstrapper/dotnet-tool/windows -OutFile build.ps1
 if ($prNo = $env:APPVEYOR_PULL_REQUEST_NUMBER) {
     Write-Host "PR Build, creating an explicit branch"
-    git fetch --unshallow
-    git config remote.origin.fetch "+refs/heads/*:refs/remotes/origin/*"
-    git fetch origin
-    git branch master origin/master
-    git checkout -b "pr-build-$prNo"
+    git checkout -qb "pr-build-$prNo"
 }