Restores melee crits

During martial arts buff removal, (I'm not good at git or github, apparently it's revision 81e4624 but I can't find it) too much code got removed.

Two "if"s and their respective num_crits++ in scored_crit in src/melee.cpp got removed entirely, rather than just having their obsolete parts cut out. As a result it's impossible to score a melee crit in current version.

I restored the missing "if"s without the obsolete parts.