elasticsearch/elasticsearch — pull request #8599 by s1monw (2014-11-21 20:02:15+00:00)
Title: [STORE] Use Lucene checksums if segment version is >= 4.9.0

We started to use the lucene CRC32 checksums instead of the legacy Adler32
in `v1.3.0` which was the first version using lucene `4.9.0`. We can safely
assume that if the segment was written with this version that checksums
from lucene can be used even if the legacy checksum claims that it has a Adler32
for a given file / segment.

Closes #8587

NOTE: this PR is against 1.x but will apply to master too but since it needs to pass BWC tests opened it against 1.x