switched back on index deletion (was accidently off because new jetty

framework delivers never null to post arguments .. there may be more of
that kind of problems)

htroot/IndexControlURLs_p.java

@@ -84,7 +84,7 @@ public class IndexControlURLs_p {
         List<File> dumpFiles =  segment.fulltext().dumpFiles();
         prop.put("dumprestore_dumpfile", dumpFiles.size() == 0 ? "" : dumpFiles.get(dumpFiles.size() - 1).getAbsolutePath());
         prop.put("dumprestore_optimizemax", 10);
-        prop.put("cleanup", post == null ? 1 : 0);
+        prop.put("cleanup", post == null || post.size() == 0 ? 1 : 0);
         prop.put("cleanup_solr", segment.fulltext().connectedRemoteSolr() ? 1 : 0);
         prop.put("cleanup_rwi", segment.termIndex() != null && !segment.termIndex().isEmpty() ? 1 : 0);
         prop.put("cleanup_citation", segment.connectedCitation() && !segment.urlCitation().isEmpty() ? 1 : 0);

source/net/yacy/http/servlets/SolrServlet.java

@@ -29,7 +29,6 @@ import java.io.Writer;
 import java.net.URL;
 import java.util.Date;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 
 import javax.servlet.Filter;
@@ -51,7 +50,6 @@ import net.yacy.cora.federate.solr.responsewriter.GrepHTMLResponseWriter;
 import net.yacy.cora.federate.solr.responsewriter.HTMLResponseWriter;
 import net.yacy.cora.federate.solr.responsewriter.OpensearchResponseWriter;
 import net.yacy.cora.federate.solr.responsewriter.YJsonResponseWriter;
-import net.yacy.cora.federate.solr.responsewriter.OpensearchResponseWriter.ResHead;
 import net.yacy.search.Switchboard;
 import net.yacy.search.SwitchboardConstants;
 import net.yacy.search.query.AccessTracker;
@@ -66,7 +64,6 @@ import org.apache.solr.common.params.CommonParams;
 import org.apache.solr.common.params.DisMaxParams;
 import org.apache.solr.common.params.MultiMapSolrParams;
 import org.apache.solr.common.util.NamedList;
-import org.apache.solr.common.util.SimpleOrderedMap;
 import org.apache.solr.core.SolrCore;
 import org.apache.solr.request.SolrQueryRequest;
 import org.apache.solr.request.SolrRequestInfo;