Fix notifications for ForeignKey fields

Fix notifications for ForeignKey fields

Instead of reporting the integer value of the foreign key, we should
report the text value from the related object. This makes the new
submissions more readable, and also makes the system not throw an
exception when trying to diff (as integers cannot be diffed).

THis seems to have broken around the time of the 1.8 upgrade, just went
unnoticed for a long time probably because changing things like which
organization owns a news item doesn't happen very often.