Enable handle-less I/O again.

This requires go-fuse that has patch
Ia09d77eae0f1af8bce46b07f386fdda20b2ccb95.

Change-Id: Ib2ef142b839a30a9415a49622f64a85bb9462021

fs/gitilesfs.go

diff --git a/fs/gitilesfs.go b/fs/gitilesfs.go
index 6131d9b..16b1d96 100644
--- a/fs/gitilesfs.go
+++ b/fs/gitilesfs.go
@@ -44,9 +44,6 @@
 	tree    *gitiles.Tree
 	opts    GitilesOptions
 
-	// TODO(hanwen): enable this again. After mount, set this to
-	// server.KernelSettings().Flags&fuse.CAP_NO_OPEN_SUPPORT != 0.
-	// This requires a suitably new kernel, though.
 	handleLessIO bool
 
 	// OID => path
@@ -437,5 +434,9 @@
 
 	// We don't need the tree data anymore.
 	r.tree = nil
+
+	if fsConn.Server().KernelSettings().Flags&fuse.CAP_NO_OPEN_SUPPORT != 0 {
+		r.handleLessIO = true
+	}
 	return nil
 }