Propagate Flags from setstat packet to request

Had file attributes, but not the flags which are required for the
attributes to be meaningful. The stats stuff in the request-server is
very simplistic, but I want it to be able to be used even if a PITA.
diff --git a/request.go b/request.go
index 7196f05..f21aca8 100644
--- a/request.go
+++ b/request.go
@@ -17,6 +17,7 @@
 	// Rmdir, Mkdir, List, Readlink, Symlink
 	Method   string
 	Filepath string
+	Flags    uint32
 	Attrs    []byte // convert to sub-struct
 	Target   string // for renames and sym-links
 	// packet data
@@ -47,6 +48,7 @@
 	request.pkt_id = pkt.id()
 	switch p := pkt.(type) {
 	case *sshFxpSetstatPacket:
+		request.Flags = p.Flags
 		request.Attrs = p.Attrs.([]byte)
 	case *sshFxpRenamePacket:
 		request.Target = filepath.Clean(p.Newpath)