Crash on records list endpoint when the collection is empty and readonly is true

[leplatrem]

When the collection has no record and was never reached, a timestamp is stored.

This does not work if readonly is true because the user does not have the permission to insert into the timestamp table.

We should not try to bump the timestamp when readonly is true.

See:

• collection_timestamp on an empty collection get updated at each request with postgresql backend. #433
• Fix empty collections timestamps with PostgreSQL mozilla-services/cliquet#649

[leplatrem]

'cuz of this: https://github.com/mozilla-services/cliquet/blob/3.1.2/cliquet/storage/postgresql/schema.sql#L154-L157

[Natim]

I believe this has been fixed with: mozilla-services/cliquet#698

[Natim]

I might be wrong.

[Natim]

Is it possible to silently log the timestamp query error?