With the new dial-stdio command the dialer is split
from `Client` function in order to access it directly.

This breaks the custom connhelpers functionality
as support for connhelpers is a feature of the default
dialer. If client defines a custom dialer then only
it is used without extra modifications. This means
that remote driver dialer needs to detect the
connhelpers on its own.

Signed-off-by: Tonis Tiigi <[email protected]>
(cherry picked from commit 8f576e5)