Use dep in Jenkinsfile

Jenkinsfile

@@ -11,7 +11,8 @@ pipeline {
             steps {
                 sh "rm -rf '${GOPATH}/src/git.cacert.org' ; mkdir -p '${GOPATH}/src/git.cacert.org'"
                 sh "ln -s '${pwd()}' '${GOPATH}/src/git.cacert.org/cacert-boardvoting'"
-                sh "cd '${GOPATH}/src/git.cacert.org/cacert-boardvoting' ; go get"
+                sh "go get -u github.com/golang/dep/cmd/dep"
+                sh "cd '${GOPATH}/src/git.cacert.org/cacert-boardvoting' ; dep ensure -v"
             }
         }
         stage('Build') {