SOLR-5590: Upgrade HttpClient/HttpComponents to 4.3.x.


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1555004 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5564: hl.maxAlternateFieldLength should apply to original field when fallback field does not exist

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1555035 13f79535-47bb-0310-9956-ffa450edef68