SUNRPC: Clear the connect flag when socket state is TCP_CLOSE_WAIT

commit d0bea455 upstream.

This is needed to ensure that we call xprt_connect() upon the next
call to call_connect().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>