Revert "loopd: avoid panic if asset client is not set"

This reverts commit d12dc03.

Author: hieblmi

loopd/swapclient_server.go

@@ -418,20 +418,11 @@ func (s *swapClientServer) marshallSwap(ctx context.Context,
 		outGoingChanSet = loopSwap.OutgoingChanSet
 
 		if loopSwap.AssetSwapInfo != nil {
-			var (
-				// Default the asset name to "N/A" in case we
-				// can't fetch it due to the asset client not
-				// being set.
-				assetName string = "N/A"
-				err       error
+			assetName, err := s.assetClient.GetAssetName(
+				ctx, loopSwap.AssetSwapInfo.AssetId,
 			)
-			if s.assetClient != nil {
-				assetName, err = s.assetClient.GetAssetName(
-					ctx, loopSwap.AssetSwapInfo.AssetId,
-				)
-				if err != nil {
-					return nil, err
-				}
+			if err != nil {
+				return nil, err
 			}
 
 			assetInfo = &looprpc.AssetLoopOutInfo{