Ensure response with needs repair contains the correct value
Ensure response with needs repair contains the correct value

For example we may have responses like (1-foo, 2-bar, 1-foo) where we've
reached a quorum with 1-foo but 1-foo is an ancestor of 2-bar which is the
correct answer. In this case we don't want to respond with 1-foo. This patch
ensures that after remove_ancestors is called the remaining response is the
same as the one that made quorum. So (1-foo, 2-bar, 2-bar) would respond with
2-bar needs repair and (1-foo, 2-bar, 1-foo) would block with read repair.

BugzID:13003

fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb