Sonatype OSS repo is returning 301 (permanently moved) for http URLs, which aren't followed by Maven Ant Tasks (artifact:dependencies), and cause the build to fail. Switching the base Sonatype OSS repo to https to see if that fixes the problem. (merged trunk r1607063)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1607054 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5798: Optimize MultiDocsEnum reuse

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1607055 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5786: Unflushed/ truncated events file (hung testing subprocess). Updating RR to 2.1.6

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1607060 13f79535-47bb-0310-9956-ffa450edef68