SOLR-5583: ConcurrentUpdateSolrServer#blockUntilFinished may wait forever if the executor service is shutdown.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1554053 13f79535-47bb-0310-9956-ffa450edef68
tests: raise connect timeout from 15 to 30

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1554056 13f79535-47bb-0310-9956-ffa450edef68
tests: remove so timeout

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1554058 13f79535-47bb-0310-9956-ffa450edef68
tests: improve this test

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1554060 13f79535-47bb-0310-9956-ffa450edef68