SOLR-5811: The Overseer will retry work items until success, which is a serious problem if you hit a bad work item. (merged branch_4x r1574281)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_7@1581184 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5811: Additional cleanup and improve logged message. (merged branch_4x r1574581 and r1574763)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_7@1581193 13f79535-47bb-0310-9956-ffa450edef68