MySQL fix for changing null value on many to many relations

[Christopher Allan Webber]

This might seem silly, as technically as a many-to-many the null value
doesn't really do anything. But I got stuck due to the fact that
django-evolution was throwing an error, putting a None in the sql
commands it generated. This patch fixes the error.

[Russell Keith-Magee]

Thanks, Christopher.

Two things:

1) This should be opened as a ticket on the Evolution ticket tracker.
This ensures that I don't forget about the problem, and allows anyone
else with the same problem knows that a fix is available

2) A patch with a fix is great, but that isn't enough - I need a test
case too. Ideally, this would be part of your patch, integrated into
the Evolution test suite. However, I would also accept a set of sample
before+ after models that comprise a minimal test case - that is, a
pair of models that fail before you apply your patch, but pass once it
has been applied.

Yours,
Russ Magee %-)

[Christopher Allan Webber]

Alright... I'll follow through on that :)