Missing checking of max voting attemps

[afalaleev]

Description
Changing of max_vote_changes_param.max_vote_changes to less value will affect attempts to change existing voting:

golos.contracts/golos.publication/golos.publication.cpp

Line 800 in 22523f1

eosio::check(vote_itr->count != max_vote_changes_param.max_vote_changes, "You can't revote anymore.");

Decision
Change compare from != to <:

golos.contracts/golos.publication/golos.publication.cpp

Line 800 in 22523f1

eosio::check(vote_itr->count != max_vote_changes_param.max_vote_changes, "You can't revote anymore.");