CHANGELOG: remove disused file

There's no reason to keep this here; the versions described are
ancient. Everything here is still mirrored on
https://wiki.qemu.org/ChangeLog/old

 if anyone is curious; otherwise, use
the git history.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20201026195131.13848-1-jsnow@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

README.rst

@@ -134,6 +134,14 @@ For additional information on bug reporting consult:
 * `<https://qemu.org/Contribute/ReportABug>`_
 
 
+ChangeLog
+=========
+
+For version history and release notes, please visit
+`<https://wiki.qemu.org/ChangeLog/>`_ or look at the git history for
+more detailed information.
+
+
 Contact
 =======