Use Magnesium controller
Use Magnesium controller

As part of controller transition to being MRI, downgrade the version
used to Magnesium release. This will be bumped to Aluminium proper
during the MRI window.

Change-Id: I093e9ffff19ef7302eca5c0495927bca0e72f3ac
Signed-off-by: Robert Varga <91ae5aa8c7a9f7e57b701db766e23e544aaa6ae9@pantheon.tech>

opendaylight/bgpcep