4.0 server tests: add WRITE15 to try various-sized writes

This is a lot of writes, and could take a while.  It might be better to
choose some smaller ranges of likely-problematic values.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
README: remove build_ext setup

I think this step is actually included in the normal build step?

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
4.1 server tests: Fix some exception handling

Some of the exception handling from the nfs4.0 version of nfs4lib was missing
from the nfs4.1 of nfs4lib.

Signed-off-by: Frank S. Filz <ffilzlnx@mindspring.com>
4.1 server tests: fix cleanup

Server tests should clean up on exit.

Signed-off-by: Frank S. Filz <ffilzlnx@mindspring.com>