Fix problems when BBDB is not present and gnorb-bbdb is not loaded.

I'm experimenting with gnorb but have BBDB 2 installed, and therefore don't want to try gnorb's BBDB integration.  I don't load gnorb-bbdb, but still have to make the following changes to run gnorb without errors.

I hope that you find the patch useful.
I thought about this for a while, and I really can't figure out what difference this makes. Can you explain?