empty-mets.xml: Add empty page structure
<mets:name>ocrd/core v{{ VERSION }}</mets:name>
</mets:agent>
</mets:metsHdr>
+ <mets:structMap TYPE="PHYSICAL">
+ <mets:div DMDID="DMDPHYS_0000" ID="PHYS_0000" TYPE="physSequence">
+ </mets:div>
+ </mets:structMap>
<mets:dmdSec ID="DMDLOG_0001">
<mets:mdWrap MDTYPE="MODS">
<mets:xmlData>
