SOLR-5577: Don't start a timer on disconnect if we are already closed

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_6@1557154 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5577: fix possible race on canceling timer on close

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_6@1557155 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5577: don't start timer thread in constructor

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_6@1557157 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5577: don't start timer thread on expiration

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_6@1557160 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5577: timer thread should be run as daemon

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_6@1557161 13f79535-47bb-0310-9956-ffa450edef68