[address-book-app] cannot partially delete address

In the phone contacts app, one type of field is a mailing address. It's a compound field with areas for city, street, country, etc... These fields are editable, but I've found that I cannot delete part of an address (for example, city) unless I delete the entire address record and create a new one minus that one piece.

This was on krillin rtm image 188.

To reproduce this bug:
1. Create a contact.
2. Add an address field to the contact, and fill out all sub-fields.
3. Save the contact.
4. Go back to edit the contact.
5. Tap one of the address sub-fields, then tap the "X" which appears to the right.
6. Attempt to save the contact with the checkmark icon.
7. Look at the contact details to see if it updated.

Expected results: The contact's address should no longer have the removed field.

Actual results: The contact's address remains the same as before.

Additionally, when I went back to reproduce this issue on the same contact (I fully deleted the address field, saved, then came back and added a new one), the contacts app crashed while trying to save with a new address. This might provide a hint about what failed.