Inconsistent counts between search() and execute() when using min_score

[ipsbrittainm]

The min_score is a top-level argument in the body, which must currently be injected via:

s = Search().query().extra(min_score=4.0)

However, this produces different counts between the count() and the execute() functions because the count() function ignores this extra data.

Search.to_dict() function:

if not count:
    d.update(recursive_to_dict(self._extra))

Related issue:
#462