Fix logging in case of source-file extraction.
Fix logging in case of source-file extraction.

That small accident makes the extraction log during the migration quite
confusing to read.

mozilla/addons-server,psiinon/addons-server,bqbn/addons-server,kumar303/addons-server,wagnerand/addons-server,mozilla/olympia,eviljeff/olympia,eviljeff/olympia,mozilla/addons-server,bqbn/addons-server,wagnerand/addons-server,aviarypl/mozilla-l10n-addons-server,diox/olympia,kumar303/olympia,diox/olympia,mozilla/addons-server,aviarypl/mozilla-l10n-addons-server,psiinon/addons-server,bqbn/addons-server,kumar303/addons-server,diox/olympia,kumar303/addons-server,kumar303/olympia,psiinon/addons-server,aviarypl/mozilla-l10n-addons-server,bqbn/addons-server,aviarypl/mozilla-l10n-addons-server,wagnerand/addons-server,mozilla/olympia,eviljeff/olympia,wagnerand/olympia,mozilla/olympia,mozilla/addons-server,wagnerand/olympia,wagnerand/addons-server,kumar303/olympia,kumar303/addons-server,wagnerand/olympia,kumar303/olympia,eviljeff/olympia,mozilla/olympia,psiinon/addons-server,wagnerand/olympia,diox/olympia