[AIRFLOW-4434] Support Impala with the HiveServer2Hook (#5206)
[AIRFLOW-4434] Support Impala with the HiveServer2Hook (#5206)

Fix support for impala in hive hook through a config option
that turns off set variable commands. Breaking changes were
introduced in [AIRFLOW-2463].

(cherry picked from commit 0ae15d84b7d2aee4119a7432578b4431b13a08ee)

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