Fix jenkins build failing because of branch name (#28)

* Remove image name in Jenkinsfile

* Update Jenkinsfile

* Update Jenkinsfile

* Update Jenkinsfile

* extra whitespace

Author: 4ndr3w

Jenkinsfile

@@ -1,12 +1,13 @@
 node {
+    def buildUUID = UUID.randomUUID().toString()
     try {
         stage('Pre-build') {
             checkout scm
             sh 'git submodule update --init --recursive'
         }
 
         stage 'Build'
-        def image = docker.build "magellan-2018-${BUILD_TAG.toLowerCase()}"
+        def image = docker.build(buildUUID)
 
         stage('Lint') {
             image.inside {
@@ -41,7 +42,7 @@ node {
     finally {
         stage('Cleanup') {
             cleanWs()
-            sh "docker rmi magellan-2018-${BUILD_TAG.toLowerCase()}"
+            sh "docker rmi ${buildUUID}"
         }
     }
 }