[cci] don't checkout the alpine branch

.circleci/config.yml

@@ -221,7 +221,6 @@ jobs:
             ssh-keyscan -H github.com >> ~/.ssh/known_hosts
             echo ${CIRCLE_REPOSITORY_URL}
             git clone --branch=weekly https://github.com/varnishcache/pkg-varnish-cache.git .
-            git checkout alpine
             tar cvzf debian.tar.gz debian --dereference
             tar cvzf redhat.tar.gz redhat --dereference 
             tar cvzf alpine.tar.gz alpine --dereference