vfs_catia: Fix bug 11827, memleak

vfs_catia: Fix bug 11827, memleak

add_srt should add the mappings to the linked list even if
mappings==NULL (the default)

Bug: https://bugzilla.samba.org/show_bug.cgi?id=11827
Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
Autobuild-User(master): Ralph Böhme <slow@samba.org>
Autobuild-Date(master): Mon Apr 11 14:25:59 CEST 2016 on sn-devel-144

(cherry picked from commit 3e2af1568d150de1cb12fef40580f4880ac787ff)

Autobuild-User(v4-2-test): Karolin Seeger <kseeger@samba.org>
Autobuild-Date(v4-2-test): Mon Apr 18 15:44:50 CEST 2016 on sn-devel-104