Fix the this_month/last_month logic
Fix the this_month/last_month logic

acmiyaguchi/data-pipeline,mozilla-services/data-pipeline,acmiyaguchi/data-pipeline,sapohl/data-pipeline,whd/data-pipeline,acmiyaguchi/data-pipeline,sapohl/data-pipeline,acmiyaguchi/data-pipeline,sapohl/data-pipeline,whd/data-pipeline,whd/data-pipeline,mozilla-services/data-pipeline,whd/data-pipeline,mozilla-services/data-pipeline,sapohl/data-pipeline,mozilla-services/data-pipeline