[AIRFLOW-5436] Remove log from init in BigQuery operators
[AIRFLOW-5436] Remove log from init in BigQuery operators

(cherry picked from commit 95388d156f90e354a41afb2cbdf9272cb4921170)

owlabs/incubator-airflow,owlabs/incubator-airflow,owlabs/incubator-airflow,owlabs/incubator-airflow