nfs4.0: Refetch lease_time after clientid update

RFC 7530 requires us to refetch the lease time attribute once a new
clientID is established. This is already implemented for the
nfs4.1(+) clients by nfs41_init_clientid, which calls
nfs41_finish_session_reset, which calls nfs4_setup_state_renewal.

To make nfs4_setup_state_renewal available for nfs4.0, move it
further to the top of the source file to include it regardles of
CONFIG_NFS_V4_1 and to save a forward declaration.

Call nfs4_setup_state_renewal from nfs4_init_clientid.

Signed-off-by: Donald Buczek <buczek@molgen.mpg.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>