import part for: "related fdo#45266, don't write extension elements into

... ODF namespaces"

See master commit 88d3931d92bc89519acf95f0510f6f2a6ff7c72c

Change-Id: I8ec31d026f5c6fdc4b7fc573060e7837a337d50b
Signed-off-by: Michael Stahl <mstahl@redhat.com>