[ci] fixed mac setup

extra/azure-pipelines/build-mac.yml

@@ -15,10 +15,10 @@ jobs:
         submodules: recursive
       - script: |
           set -ex
-          brew uninstall [email protected]
-          brew uninstall [email protected]
-          brew untap local/openssl
-          brew untap local/python2
+          # brew uninstall [email protected]
+          # brew uninstall [email protected]
+          # brew untap local/openssl
+          # brew untap local/python2
           brew update || brew update || brew update
           # brew unlink python@2
           brew bundle --file=tests/Brewfile --no-upgrade || brew link --overwrite awscli