Don't delete stats index -- no longer exists; core is disabled now.

build.xml

@@ -183,7 +183,6 @@
 
     <!-- delete the configuration, sample index, logs and cache data -->
     <delete dir="${srcdir}/solr/alphabetical_browse" includeemptydirs="true" failonerror="true" />
-    <delete dir="${srcdir}/solr/stats/index" includeemptydirs="true" failonerror="true" />
     <delete dir="${srcdir}/solr/authority/index" includeemptydirs="true" failonerror="true" />
     <delete dir="${srcdir}/solr/authority/tlog" includeemptydirs="true" failonerror="true" />
     <delete dir="${srcdir}/solr/biblio/index" includeemptydirs="true" failonerror="true" />