Ticket #2097: ChangeLog in its current form does not strictly make any sense

The suggested wording makes it explicit where to look for the
traditional list of changes since the last release and how to obtain a
detailed log of changes.

Signed-off-by: Yury V. Zaytsev <yury@shurup.com>

ChangeLog

@@ -1,2 +1,3 @@
-See
-git log
+For the major changes since the last release please see doc/NEWS. For
+the detailed commit log please refer to the output of 'git log' against
+a checked out copy of the repository.