Deprecate bind_host parameter

Since Icehouse release, bind_host parameter has been deprecated for two
new flags: public_bind_host and admin_bind_host: http://git.io/RGao7w

This patch deprecates bind_host param and ensure backward compatibility
and configure Keystone using the two new flags.

Closes-bug: #1271269

Change-Id: I60db96fc99311280ae5051e1d9cfb5d46b3374a2
Signed-off-by: Emilien Macchi <emilien.macchi@enovance.com>