fix(bitswap/loop) add to wantlist just once

oops

set Add is idempotent but it's a waste of resources

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

exchange/bitswap/bitswap.go

@@ -188,9 +188,6 @@ func (bs *bitswap) run(ctx context.Context) {
 			}
 		case ks := <-bs.batchRequests:
 			// TODO: implement batching on len(ks) > X for some X
-			for _, k := range ks {
-				bs.wantlist.Add(k)
-			}
 			if len(ks) == 0 {
 				log.Warning("Received batch request for zero blocks")
 				continue