LUCENE-6049: don't throw exc writing segment if document hit non-aborting exc

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1637524 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-6049: changes entry

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1637529 13f79535-47bb-0310-9956-ffa450edef68
woops

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1637530 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-6039: add another null check

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1637541 13f79535-47bb-0310-9956-ffa450edef68