Minor fixes

src/main/java/org/gcube/informationsystem/resourceregistry/types/TypeManagement.java

@@ -798,7 +798,11 @@ public class TypeManagement {
 			oSchema.dropClass(typeName);
 			
 			ElementManagement<?,?> erManagement = getTypeManagement(accessType, typeName);
-			erManagement.delete();
+			// If we need to delete an internal type for maintenance we this this check
+			// otherwise we have a null pointer exception
+			if(erManagement!=null) {
+				erManagement.delete();
+			}
 			
 			oDatabaseDocument.commit();