Lucene/Solr 4.3.1 release tag

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/tags/lucene_solr_4_3_1@1492801 13f79535-47bb-0310-9956-ffa450edef68
Merge commit '31fb4d7a87d483118f7784a602677f50827c6dda' into lucene_solr_4_3
Added https://issues.apache.org/jira/browse/SOLR-1093 patch - MultiSearchHandler (component)