s3-printing: fix migrate printer code (bug 8618)

s3-printing: fix migrate printer code (bug 8618)

Removed path from driver files.
We only need the basenames.
(cherry picked from commit d61993043fcb7676a58658476421f5f4ff1a3fea)
(cherry picked from commit 9f07ef2249dc21eab37cd5888623e6edc84b2b59)

BUG: https://bugzilla.samba.org/show_bug.cgi?id=8618

Reviewed-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Günther Deschner <gd@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Wed Oct  5 19:19:39 CEST 2016 on sn-devel-144