Fix another analyzer complaint, about potentially calling close(fd)
for a file descriptor number that has already been closed. This time
it was right, although I think nothing bad would happen if that
occurred.
With the original code, veryold() might succeed and close the file,
then clearoldlocks() fail so skip 'goto gotlock'. Then the already
closed file would passed to close() again.
Normal usage still works. No testing using failure conditions has
been done.
90f9b0742e