hedgewars-engine (rust): fix "protocol_version" -> "hedgewars_engine_protocol_version"
That function/symbol was renamed in ef2fc0210362
/*
** $Id: lapi.h,v 2.2.1.1 2007/12/27 13:02:25 roberto Exp $
** Auxiliary functions from Lua API
** See Copyright Notice in lua.h
*/
#ifndef lapi_h
#define lapi_h
#include "lobject.h"
LUAI_FUNC void luaA_pushobject (lua_State *L, const TValue *o);
#endif