adjust error message for file not found

weed/storage/needle/needle_read_write.go

@@ -174,7 +174,7 @@ func ReadNeedleBlob(r *os.File, offset int64, size uint32, version Version) (dat
 func (n *Needle) ReadBytes(bytes []byte, offset int64, size uint32, version Version) (err error) {
 	n.ParseNeedleHeader(bytes)
 	if n.Size != size {
-		return fmt.Errorf("File Entry Not Found. offset %d, Needle id %d expected size %d Memory %d", offset, n.Id, n.Size, size)
+		return fmt.Errorf("entry not found: offset %d found id %d size %d, expected size %d", offset, n.Id, n.Size, size)
 	}
 	switch version {
 	case Version1: