image_builder: fix syntax

.travis.yml

@@ -1,9 +1,3 @@
-# More info there
-# https://github.com/travis-ci/travis-ci/issues/6893
-# https://docs.travis-ci.com/user/customizing-the-build/
-# https://docs.travis-ci.com/user/deployment/releases
-# https://docs.travis-ci.com/user/environment-variables/
-
 sudo: required
 language: generic
 services:
@@ -28,7 +22,7 @@ git:
 before_script:
   - docker pull ${DOCKER}
 script:
-  - [[ -z TARGET_REF ]] || exit 1
+  - [[ -z TARGET_REF ]]
   - docker run --privileged --rm -v /dev:/dev -v ${BUILD_DIR}:/builder/image -e "TARGET_REPO=${TARGET_REPO}" -e "TARGET_REF=${TARGET_REF}" ${DOCKER}
 # after_failure:
 #   - skip_deploy: true
@@ -46,3 +40,9 @@ deploy:
   skip_cleanup: true
   on:
     tags: true
+
+# More info there
+# https://github.com/travis-ci/travis-ci/issues/6893
+# https://docs.travis-ci.com/user/customizing-the-build/
+# https://docs.travis-ci.com/user/deployment/releases
+# https://docs.travis-ci.com/user/environment-variables/