Merge pull request #3590 from ipfs/kevina/blockservice-nit

blockservice: avoid using unnecessary continue statement

blockservice/blockservice.go

@@ -112,11 +112,10 @@ func (s *blockService) AddBlocks(bs []blocks.Block) ([]*cid.Cid, error) {
 			if err != nil {
 				return nil, err
 			}
-			if has {
-				continue
-			}
+			if !has {
 				toput = append(toput, b)
 			}
+		}
 	} else {
 		toput = bs
 	}