Fix memory leak

This occurs when slave nodes harvest the master nodes, while the
master node is harvesting. The TaxonomyReader is never closed,
which results in high memory consumption.
I could not find any usage in the code where closing the
TaxonomyReader would result in any issues.

Author: koplas

core/src/main/java/org/fao/geonet/kernel/search/IndexAndTaxonomy.java

@@ -44,7 +44,6 @@ public IndexAndTaxonomy(long version, GeonetworkMultiReader indexReader, Taxonom
     @Override
     public void close() throws IOException {
         indexReader.releaseToNRTManager();
-        //TODO: this has a taxonomyReader in it, and it should be "closed" (decrement a ref)
-        // However, since it's public, not sure if we can do that or not since someone else might be using it...
+        taxonomyReader.close();
     }
 }

core/src/main/java/org/fao/geonet/kernel/search/SearchManager.java

@@ -1208,7 +1208,7 @@ public IndexAndTaxonomy getNewIndexReader(String preferredLang) throws IOExcepti
     }
 
     public void releaseIndexReader(IndexAndTaxonomy reader) throws InterruptedException, IOException {
-        reader.indexReader.releaseToNRTManager();
+        reader.close();
     }
 
     /**