fs: dlm: handle non blocked connect event

The manpage of connect shows that in non blocked mode a writeability
indicates successful connection event. This patch is handling this event
inside the writeability callback. In case of SCTP we use blocking
connect functionality which indicates a successful connect when the
function returns with a successful return value.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>