Go back to using microtime() to get the timestamps for {f,l,}utimes(path,

Go back to using microtime() to get the timestamps for {f,l,}utimes(path,
NULL) for now.  Bruce says I jumped the gun with my change in
revision 1.131, or maybe it should use nanotime(), or maybe it
shouldn't be decided in the VFS layer at all.  I'm leaving it with
the old behavior until the Trans-Pacific Internet Vulcan Mind Meld
yields fuller understanding.