Core: upgrade to Lucene 4.9.1 bugfix release

Author: mikemccand

pom.xml

@@ -31,7 +31,7 @@
     </parent>
 
     <properties>
-        <lucene.version>4.9.0</lucene.version>
+        <lucene.version>4.9.1</lucene.version>
         <tests.jvms>auto</tests.jvms>
         <tests.shuffle>true</tests.shuffle>
         <tests.output>onerror</tests.output>