SOLR-5232: fix retry logic

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1538112 13f79535-47bb-0310-9956-ffa450edef68
tests: blockUntilFinished when stopping concurrent solrserver

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1538126 13f79535-47bb-0310-9956-ffa450edef68