Fix false https oaipmh xsi:namespace to http

oaipmh-core/src/main/java/info/textgrid/middleware/OAIPMHImpl.java

@@ -32,7 +32,7 @@ import info.textgrid.middleware.oaipmh.VerbType;
  * 
  * @author Maximilian Brodhun, SUB Göttingen
  * @author Stefan E. Funk, SUB Göttingen
- * @version 2019-10-18
+ * @version 2019-10-21
  * @since 2014-01-29
  */
 public class OAIPMHImpl implements OAIPMHProducer {
@@ -42,7 +42,7 @@ public class OAIPMHImpl implements OAIPMHProducer {
   // **
 
   private static final String OAIPMH_SCHEMA_LOCATION =
-      "http://www.openarchives.org/OAI/2.0/ https://www.openarchives.org/OAI/2.0/OAI-PMH.xsd";
+      "http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd";
   private static final String OAIDC_SCHEMA_LOCATION =
       "http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd";
   private static final String DC_SCHEMA_LOCATION =