Fix an even sillier typo that broke compile

--HG--
branch : trunk

src/server/game/Server/Protocol/Handlers/GroupHandler.cpp

@@ -126,7 +126,7 @@ void WorldSession::HandleGroupInviteOpcode(WorldPacket & recv_data)
     if (group)
     {
         // not have permissions for invite
-        if (!group->IsLeader(GetPlayer()->GetGUID() && group->IsAssistant(GetPlayer()->GetGUID())
+        if (!group->IsLeader(GetPlayer()->GetGUID() && group->IsAssistant(GetPlayer()->GetGUID())))
         {
             SendPartyResult(PARTY_OP_INVITE, "", ERR_NOT_LEADER);
             return;