Changes

templates: osmo-mgw.cfg.tmpl: address deprecation warnings

This commit fixes the following deprecation warnings:

range must end at an odd port number, autocorrecting port (16000) to: 16001
% Deprecated 'sdp audio-payload number <0-255>' config no longer has any effect
% Deprecated 'sdp audio-payload name NAME' config no longer has any effect

Change-Id: I98549abf8dd726fcc67a1de6a5f8bee64558883d