import part for "put that attribute into an extension namespace"

See master commit 6f55edf340ea83d02e5ba60d05df868a4a04a2c0

Change-Id: Ie3618e44416a0765877e4b09e41e058d2808cdee
Signed-off-by: Michael Stahl <mstahl@redhat.com>
(cherry picked from commit b8159be15ae420d58dbf27dff0af80f2856a038f)
Reviewed-on: https://gerrit.libreoffice.org/13382
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>