When we change a nullable column to a non-nullable column, we can get a
data truncation error if any value was "NULL".
This is exceptionally unusual, but our two very oldest Herald rules have
a "NULL" policy on `secure`.
Summary:
Depends on D18926. Ref T6203. Ref T13048. Herald rule repetition policies are stored as integers but treated as strings in most contexts.
After D18926, the integer stuff is almost totally hidden inside `HeraldRule` and getting rid of it completely isn't too tricky.
Do so now.
Test Plan:
- Created "only the first time" and "every time" rules. Did a SELECT on their rows in the database.
- Ran migrations, got a clean bill of health from `storage adjust`.
- Did another SELECT on the rows, saw a faithful conversion to strings "every" and "first".
- Edited and reviewed rules, swapping them between "every" and "first".
Reviewers: amckinley
Reviewed By: amckinley
Maniphest Tasks: T13048, T6203
Differential Revision: https://secure.phabricator.com/D18927
