Fix errors in migration to V3

Fix errors in migration to V3

Fix a tiny error in the migration script and improve it.

Fix declaration of afb_daemon_get... without args for
binding V3 compatibility.

Fix declaration of afb_api_event_handler_...

Fix the correct URL to the sed script:
 valid:   https://git.automotivelinux.org/src/app-framework-binder/plain/docs/migration-to-binding-v3.sed
 invalid: https://git.automotivelinux.org/src/app-framework-binder/tree/docs/migration-to-binding-v3.sed

Bug-AGL: SPEC-1595

Change-Id: I245b20a9c14634a94c69420312afbd97628bc750
Signed-off-by: José Bollo <jose.bollo@iot.bzh>