Fix: align bindingv2 struct with dab appfw version

Fix: align bindingv2 struct with dab appfw version

DAB Fixes follows appfw API break.

Following functions now return 0 on success and negative value
on failure :
    o afb_req_subcall
    o afb_req_subcall_sync
    o afb_service_call
    o afb_service_call_sync

Verbosity macros used in v2 bindings now needs to be prefixed
with AFB_ (ERROR -> AFB_ERROR)

New field for afb_verb_v2 and afb_binding_v2 structures

Fix: uninitialized variables.

Change-Id: Ia728b9ac4576b9b44c8c7c054820b7c64a314942
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>