Jenkinsfile: remove .git mount in stages that don't use it
The .git mount is only needed for the DCO check, and for building
the binaries if `DOCKER_GITCOMMIT` is not set.
@@ -54,7 +54,6 @@ pipeline {
sh '''
docker run --rm -t --privileged \
-v "$WORKSPACE/bundles:/go/src/github.com/docker/docker/bundles" \
- -v "$WORKSPACE/.git:/go/src/github.com/docker/docker/.git" \
--name docker-pr$BUILD_NUMBER \
-e DOCKER_GITCOMMIT=${GIT_COMMIT} \
-e DOCKER_GRAPHDRIVER \
