SUNRPC: Fail over more quickly on connect errors

We should not allow soft tasks to wait for longer than the major timeout
period when waiting for a reconnect to occur.

Remove the field xprt->connect_timeout since it has been obsoleted by
xprt->reestablish_timeout.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>