[PATCH] doc: only distribute 5 years of ChangeLogs

[Pádraig Brady]

Our ChangeLogs are increasing in size and age,
so the attached will only distribute ChangeLogs
since 8.15 (Jan 2012).

That will change the dist sizes from:
  734,084 ChangeLog-concat.xz
3,254,436 ChangeLog-concat

to:
  163,276 ChangeLog.xz
  619,945 ChangeLog

Note coreutils-8.26.tar.xz was 5.7MB,
so a 10% saving is significant.

cheers,
Pádraig