Use a provider for Xff blocking tests

Move the block insertion to addDBData(), and use a provider to
itterate through the test strings.

This seems like the more correct way to run these tests, although it
still seems hacky, since the db isn't cleaned up after each test.

Change-Id: Ib22ce69797ec03a61b0cc330e8572865290ebd31
Merge "Use a provider for Xff blocking tests"