Handle Stack#maximum_commits_per_deploy being nil
Handle Stack#maximum_commits_per_deploy being nil

Shopify/shipit-engine,perobertson/shipit-engine,perobertson/shipit-engine,perobertson/shipit-engine,perobertson/shipit-engine,Shopify/shipit-engine,perobertson/shipit-engine,Shopify/shipit-engine,Shopify/shipit-engine,Shopify/shipit-engine