more pynfs tests

Casey's been finding some delegation bugs, so I added a few more delegation tests, all available from the master branch of

git://linux-nfs.org/~bfields/pynfs.git

--b.

commit 89d04c11546fa5b73fc5d9fff985c848f13e35a7

Author: J. Bruce Fields <[email protected]>
Date:   Mon Jun 6 21:13:16 2011 -0400

TESTS: test that RENAME over a file recalls a delegation

commit bc16acebfec0d18fd0290cafba640ffee652701b

Author: J. Bruce Fields <[email protected]>
Date:   Mon Jun 6 21:10:36 2011 -0400

TESTS: test that RENAME recalls delegation

commit 123281663c7845c9f2f10411cee969a4aa5a9ce4

Author: J. Bruce Fields <[email protected]>
Date:   Mon Jun 6 19:50:51 2011 -0400

TESTS: test that LINK recalls delegation

commit d9059bc0dba5333a56387ec11a5d592a0d54af1a

Author: J. Bruce Fields <[email protected]>
Date:   Mon Jun 6 21:14:49 2011 -0400

TESTS: don't wait as long on delegation tests

I can't see the advantage of 5 second waits and exponential backoff. Normally this will be fast.

commit be00fef805658b0d3ff889ab30fa51c976a3c1b2

Author: J. Bruce Fields <[email protected]>
Date:   Mon Jun 6 18:58:45 2011 -0400

TESTS: factor out retry loop from DELEG15