NFSv4: Set the connection timeout to match the lease period

Set the timeout for TCP connections to be 1 lease period to ensure
that we don't lose our lease due to a faulty TCP connection.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>