without the directory timeout expiring, we get vattr_null as the
attributes for that file. Ensure that we always report sane
attributes by getting them from the server if this is the case.
(also, sprinkle some const)
Fixes problem reported by dyoung. But wait! The bug's medallion
begins to glow! The bug looks much better! I crumble to dust.
There's probably another similar bug related to "lazy open". It
will trigger if we reclaim a node before the response to the open
arrives. Even the comments (typoless) know about this bug ...
But verifying it exists and fixing it will have to wait for another
day.
326638b53f