Revert "add pull before build"

This reverts commit f5994ffb

.gitlab-ci.yml

@@ -7,7 +7,7 @@ build:
     stage: build
     script:
         - docker login $CI_REGISTRY -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD
-        - docker build -pull -t $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG .
+        - docker build -t $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG .
         - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG
         - if [ "$CI_COMMIT_REF_NAME" = "master" ]; then docker tag $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG $CI_REGISTRY_IMAGE; fi
         - if [ "$CI_COMMIT_REF_NAME" = "master" ]; then docker push $CI_REGISTRY_IMAGE; fi