package/oracle-mysql: use bundled GPL-2.0+ libreadline

oracle-mysql is licensed under GPL-2.0, which is not license compatible with
modern readline (GPL-3.0+), so instead use the bundled older version
(GPL-2.0+ licensed) of readline instead.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>