Adopt replicated block instead of block in rounds map

[samliok]

          we should rather adopt this block instead of what we have, because this block is the notarized one, so ours is an equivocated block.

However let's take care of this in a new PR, I want to freeze this one for major changes.

Originally posted by @yacovm in #123 (comment)

[samliok]

closed with #128