Merged revision(s) 1512937 from lucene/dev/trunk:
LUCENE-5164: Fix default chunk sizes in FSDirectory to not be unnecessarily large (now 8192 bytes); also use chunking when writing to index files. FSDirectory#setReadChunkSize() is now deprecated and will be removed in Lucene 5.0

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1512949 13f79535-47bb-0310-9956-ffa450edef68