[AIRFLOW-3263] Ignore exception when 'run' kills already killed job (#4108)
[AIRFLOW-3263] Ignore exception when 'run' kills already killed job (#4108)

Sometimes when you run tasks from command line you get exit code = 1 due
to race condition (job runner tries to get process group from the
process that has already been terminated in the meantime)
apache/airflow,mtagle/airflow,sekikn/incubator-airflow,malmiron/incubator-airflow,artwr/airflow,r39132/airflow,lyft/incubator-airflow,jgao54/airflow,Acehaidrey/incubator-airflow,mistercrunch/airflow,jgao54/airflow,spektom/incubator-airflow,Acehaidrey/incubator-airflow,lyft/incubator-airflow,lyft/incubator-airflow,spektom/incubator-airflow,danielvdende/incubator-airflow,DinoCow/airflow,nathanielvarona/airflow,airbnb/airflow,fenglu-g/incubator-airflow,wileeam/airflow,dhuang/incubator-airflow,fenglu-g/incubator-airflow,fenglu-g/incubator-airflow,r39132/airflow,nathanielvarona/airflow,mrkm4ntr/incubator-airflow,jgao54/airflow,wileeam/airflow,r39132/airflow,apache/incubator-airflow,artwr/airflow,Fokko/incubator-airflow,mtagle/airflow,Acehaidrey/incubator-airflow,adamhaney/airflow,danielvdende/incubator-airflow,Acehaidrey/incubator-airflow,airbnb/airflow,bolkedebruin/airflow,mistercrunch/airflow,sekikn/incubator-airflow,DinoCow/airflow,sekikn/incubator-airflow,wileeam/airflow,danielvdende/incubator-airflow,malmiron/incubator-airflow,lyft/incubator-airflow,sekikn/incubator-airflow,cfei18/incubator-airflow,dhuang/incubator-airflow,fenglu-g/incubator-airflow,nathanielvarona/airflow,dhuang/incubator-airflow,malmiron/incubator-airflow,jgao54/airflow,artwr/airflow,artwr/airflow,airbnb/airflow,nathanielvarona/airflow,malmiron/incubator-airflow,bolkedebruin/airflow,apache/airflow,adamhaney/airflow,Fokko/incubator-airflow,Acehaidrey/incubator-airflow,adamhaney/airflow,DinoCow/airflow,cfei18/incubator-airflow,apache/incubator-airflow,wileeam/airflow,cfei18/incubator-airflow,mrkm4ntr/incubator-airflow,dhuang/incubator-airflow,wooga/airflow,wooga/airflow,r39132/airflow,apache/incubator-airflow,bolkedebruin/airflow,apache/airflow,DinoCow/airflow,spektom/incubator-airflow,adamhaney/airflow,cfei18/incubator-airflow,cfei18/incubator-airflow,bolkedebruin/airflow,airbnb/airflow,spektom/incubator-airflow,mtagle/airflow,apache/airflow,mtagle/airflow,Fokko/incubator-airflow,bolkedebruin/airflow,danielvdende/incubator-airflow,danielvdende/incubator-airflow,apache/incubator-airflow,danielvdende/incubator-airflow,wooga/airflow,cfei18/incubator-airflow,Fokko/incubator-airflow,mrkm4ntr/incubator-airflow,mistercrunch/airflow,nathanielvarona/airflow,mistercrunch/airflow,apache/airflow,mrkm4ntr/incubator-airflow,Acehaidrey/incubator-airflow,wooga/airflow,nathanielvarona/airflow,apache/airflow