Make objects.Flavor._orig_projects a list

The projects field is a list type but the init was
defaulting it to an empty dict. This simply makes it
a list.

This was apparently not causing any problems, but it's
not correct so we might as well fix it.

Change-Id: If22514f79e5e45b15e3b777c89713f7014112d99
Merge "Make objects.Flavor._orig_projects a list"