lib/adouble: pass filesize to ad_unpack()

lib/adouble: pass filesize to ad_unpack()

ad_unpack() needs the filesize, not the capped IO size we're using in the caller
to read up to "size" bystem from the ._ AppleDouble file.

This fixes a regression introduced by bdc257a1cbac7e8c73a084b618ba642476807483
for bug 13968.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14171
RN: vfs_fruit returns capped resource fork length

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Ralph Böhme <slow@samba.org>
Autobuild-Date(master): Wed Oct 30 14:52:34 UTC 2019 on sn-devel-184

(backported from commit f3df83a2c346d945487a27a9d258ee6331ea7dbb)

Autobuild-User(v4-10-test): Karolin Seeger <kseeger@samba.org>
Autobuild-Date(v4-10-test): Fri Nov  8 14:01:11 UTC 2019 on sn-devel-144