fuse: bugfix: don't crash on startup
fuse: bugfix: don't crash on startup

When fstree is not available on startup, simply skip re-creating the
drs.

Signed-off-by: Ramkumar Ramachandra <5c355d1d38066ed0c5de420d67c1b5ed0687c4bd@gmail.com>

artagnon/phoenixfs,artagnon/phoenixfs,artagnon/phoenixfs