enable ODF export validation

Change-Id: I09f517a49507a2eb31118f88f31dc2ff8b03de6a
fix ODF validation error

that attribute was only written for backwards compatibility

Change-Id: Icf06300809c55c3a20a74ee3b9d36644d6f5c2d9
add disabled support for export validation in writer tests

Still too many validation errors to enable it.

Change-Id: I45830f6cff8ef52bc63fdda61a99985f4f7d242a