{versioncontrol_git_event_data}.ff created in two update functions, secound fails

https://github.com/niklasf/versioncontrol_git/commit/671f8675fbb92b5b5a0... adds the ff field in two update functions instead of in the schema and in one update function. https://github.com/niklasf/versioncontrol_git/commit/727c6bac665faa3c021... later adds it to the schema.

Trying to create ff twice leads to an error, obviously.