nfsd41: renew_client must be called under the state lock

Until we work out the state locking so we can use a spin lock to protect
the cl_lru, we need to take the state_lock to renew the client.

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfsd41: Do not renew state on error]
Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfsd41: Simplify exit code]
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>