Revert "Attempt to generate assets with travis"

This reverts commit 9592672ff9.

Assets generation still requires too much time...

.travis.yml

@@ -5,7 +5,7 @@ script:
   - make configure SILENT=1 CONFIGURE_OPTS="-e SETTING_ACTIVATE_NOTES=1 -e SETTING_ACTIVATE_XQUEUE=1"
   - make build
   - make databases
-  - make assets
+  #- make assets # too time-consuming
 deploy:
   provider: script
   script: docker login -u "$DOCKER_USERNAME" -p "$DOCKER_PASSWORD" && make push