As we have factored Elasticsearch into smaller libraries, we have ended
up in a situation that some of the dependencies of Elasticsearch are not
available to code that depends on these smaller libraries but not server
Elasticsearch. This is a good thing, this was one of the goals of
separating Elasticsearch into smaller libraries, to shed some of the
dependencies from other components of the system. However, this now
means that simple utility methods from Lucene that we rely on are no
longer available everywhere. This commit copies IOUtils (with some small
formatting changes for our codebase) into the fold so that other
components of the system can rely on these methods where they no longer
depend on Lucene.
5904d936fa