nfsd41: Remove ip address collision detection case

Verified that cthon and pynfs exchange id tests pass (except for the
two expected fails: EID8 and EID50)

Signed-off-by: Mike Sager <sager@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>