Upgrade to Solr 4.1

* http://wiki.apache.org/solr/ReleaseNote41

* https://issues.apache.org/jira/browse/SOLR/fixforversion/12321141#selectedTab=com.atlassian.jira.plugin.system.project%3Aversion-issues-panel

* http://lucene.apache.org/solr/4_1_0/changes/Changes.html

Run smartos benchmark to see if there is any query performance difference.