Improve delete handling code.

Change-Id: I3f09f00a2966ee246056ea11ec55d952da6aabc0
Drop blacklist number uniqueness constraint.

It's very hard to deal with that constraint in practise, so drop the
contraint from the DB and handle potential duplicate rows when querying.

Change-Id: Id28a415ba80cf100879b24de88b4b50638e900ca
Revert "telephony: Privacy Guard support"

This reverts commit 60511cf58e4308cef91b817ee546fee2040f4b69.