Never expect the replica iterators to be sorted (#538)

sftp/replica_client.go

@@ -8,7 +8,6 @@ import (
 	"net"
 	"os"
 	"path"
-	"sort"
 	"sync"
 	"time"
 
@@ -141,8 +140,6 @@ func (c *ReplicaClient) Generations(ctx context.Context) (_ []string, err error)
 		generations = append(generations, name)
 	}
 
-	sort.Strings(generations)
-
 	return generations, nil
 }
 
@@ -229,8 +226,6 @@ func (c *ReplicaClient) Snapshots(ctx context.Context, generation string) (_ lit
 		})
 	}
 
-	sort.Sort(litestream.SnapshotInfoSlice(infos))
-
 	return litestream.NewSnapshotInfoSliceIterator(infos), nil
 }
 
@@ -363,8 +358,6 @@ func (c *ReplicaClient) WALSegments(ctx context.Context, generation string) (_ l
 		})
 	}
 
-	sort.Sort(litestream.WALSegmentInfoSlice(infos))
-
 	return litestream.NewWALSegmentInfoSliceIterator(infos), nil
 }