part of "fix odf validation errors around new chart regression curves"

need MAP_ENTRY_ODF_EXT_IMPORT definition from
4c7116413af091a30f5fa60c63d29bc694730518

Change-Id: I5bd4340186beca95eb3c615f713056007fcc5ee1
Reviewed-on: https://gerrit.libreoffice.org/8629
Reviewed-by: Michael Stahl <mstahl@redhat.com>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>