Remove strictIPs(), cascadingDeletes(), and cleanupTriggers()

Remove strictIPs(), cascadingDeletes(), and cleanupTriggers()

These DatabaseBase methods have no callers are were a mistake to
begin with. They only encouraged code forking and incompatibilities
among different backing DB types.

Also removed stray realTimestamps() method that was left over
from prior removals.

Change-Id: I37bef8585151e2782d2c88b5ae1e6752109c6ac7