fix(cros_generate_update_payload): Remove duplicate chromeos-common.sh
fix(cros_generate_update_payload): Remove duplicate chromeos-common.sh

An extra source of chromeos-common.sh was added, fancier search logic
for that file already existed a couple lines down and that logic is
required for au-generator.zip

mgireesh05/dev-util,coreos/dev-util,mgireesh05/dev-util,coreos/dev-util,coreos/dev-util,mgireesh05/dev-util