sentry: remove reference to vanilla celery image
sentry: remove reference to vanilla celery image

This doesn't make sense and will never work.

See discussion on https://github.com/docker-library/docs/pull/376

vaygr/docker-library-docs,vmassol/docs,docker-flink/docs,crate/docker-docs,caoyangs/docs,chaudum/docs,vmassol/docs,pierreozoux/docs,caoyangs/docs,infosiftr/docker-library-docs,zendtech/docs,car031/docs,Bonitasoft-Community/docker_docs,avoinea/docs,emilevauge/docs,dpwspoon/docs,infosiftr/docker-library-docs,davidcurrie/docs,tilosp-docker/library-docs,31z4/docs,tilosp-docker/library-docs,nats-io/docker-docs,ceejatec/docs,testshotagit/docs,dmetzler/docker-library-docs,docker-solr/docs,nats-io/docker-docs,jperrin/docs,pierreozoux/docs,c0b/docs,jperrin/docs,Lightstreamer/docs,c0b/docs,astawiarski/docs,testshotagit/docs,dinogun/docs,pydio/docs,emilevauge/docs,vaygr/docker-library-docs,Bonitasoft-Community/docker_docs,odoo/docker-docs,docker-library/docs,Lightstreamer/docs,docker-flink/docs,jetty-project/docker-docs,pydio/docs,orientechnologies/docker-docs,astawiarski/docs,jetty-project/docker-docs,docker-library/docs,orientechnologies/docker-docs,31z4/docs,davidcurrie/docs,dinogun/docs,dpwspoon/docs,docker-solr/docs,odoo/docker-docs,zendtech/docs,avoinea/docs,car031/docs,gprivitera/docs,appropriate/docker-library-docs,ceejatec/docs,dmetzler/docker-library-docs,chaudum/docs,crate/docker-docs,gprivitera/docs,appropriate/docker-library-docs