orig_set for scalar should be set to util.Set(), not empty list []

[Former user]

Changeset 2580 "added orig_set collection to Select when its declared as a scalar, to allow corresponding_column() to return a result"

The implementation of this was incorrect. orig_set is getting set to an empty list [] instead of an empty util.Set(). This causes a traceback on certain queries that gives the error list type has no attribute 'add'

Patch included is just to change this one line of code. I didn't submit any tests with this patch because it's a no-brainer.

-Ian Charnas [e-mail]

[Mike Bayer]

test case would be enormously helpful since we'd like to have unit test coverage for every bug fixed.

changeset:2749