fixed broken DOI

metadata/mi/2017/datacite-20200826-151643-articles-1584-5.xml

 <?xml version="1.0" encoding="utf-8"?>
 <resource xmlns="http://datacite.org/schema/kernel-4" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://datacite.org/schema/kernel-4 http://schema.datacite.org/meta/kernel-4/metadata.xsd">
-  <identifier identifierType="DOI">10.21243/10.21243/medienimpulse.2016.4.973</identifier>
+  <identifier identifierType="DOI">10.21243/medienimpulse.2016.4.973</identifier>
   <creators>
     <creator>
       <creatorName>Gabriel, Sonja</creatorName>