Merge pull request #6694 from priyawadhwa/cleanup-jenkins

Clean up docker volumes in jenkins common script

hack/jenkins/common.sh

@@ -33,6 +33,9 @@ export PATH=$PATH:"/usr/local/bin/:/usr/local/go/bin/:$GOPATH/bin"
 # installing golang so we could do go get for gopogh
 sudo ./installers/check_install_golang.sh "1.13.4" "/usr/local" || true
 
+docker rm -f $(docker ps -aq) >/dev/null 2>&1 || true
+docker volume prune -f || true
+docker system df || true
 
 echo ">> Starting at $(date)"
 echo ""