Whatever was supplied by the samba package was formerly being overwritten by (or ignored because of) VASM's smb.conf copy. During this time, samba.SlackBuild failed to keep up with location changes in Samba's source tree; probably not noticed because the other, outdated copy was there. Samba's slackbuild needs to be updated and probably should copy the smb.conf-example that would be generated to smb.conf IF there's not one there already.
A little more info at https://bitbucket.org/VLCore/vabs/issue/45/samba-doesnt-start-on-fresh-install
Just don't have time to go further with this one myself right now.