Seems APPVEYOR_REPO_COMMIT is not getting the commit ID properly, let's try with…

Seems APPVEYOR_REPO_COMMIT is not getting the commit ID properly, let's try with the branch name (it should be updated at this point)

appveyor.yml

@@ -136,7 +136,7 @@ install:
 clone_script:
 - cmd: git clone -q --recursive --branch=%APPVEYOR_REPO_BRANCH% https://github.com/%APPVEYOR_REPO_NAME%.git %APPVEYOR_BUILD_FOLDER%
 - cmd: git fetch
-- cmd: git checkout -qf %APPVEYOR_REPO_COMMIT%
+- cmd: git checkout -qf %APPVEYOR_REPO_BRANCH%
 
 build_script:
   # Build the compiled extension