Remove use of Docker Hub from nightly

Author: rjeberhard

Jenkinsfile.kindnightly

@@ -108,8 +108,6 @@ pipeline {
     environment {
         github_url = "${env.GIT_URL}"
         github_creds = 'ecnj_github'
-        dockerhub_username_creds = 'docker-username'
-        dockerhub_password_creds = 'docker-password'
         ocr_username_creds = 'OCR username'
         ocr_password_creds = 'OCR Password'
         ocir_registry_creds = 'ocir-server'
@@ -349,12 +347,7 @@ pipeline {
                 }
 
                 stage('Build WebLogic Kubernetes Operator') {
-                    environment {
-                        DOCKERHUB_USERNAME = credentials("${dockerhub_username_creds}")
-                        DOCKERHUB_PASSWORD = credentials("${dockerhub_password_creds}")
-                    }
                     steps {
-                        sh 'echo ${DOCKERHUB_PASSWORD} | docker login -u ${DOCKERHUB_USERNAME} --password-stdin'
                         sh "mvn -DtrimStackTrace=false clean install"
                     }
                 }