Deploying ODL without L3 DVR is no longer supported. This patch moves
the opendaylight-l3 env settings to be the new default for opendaylight
env file, while also removing any option to disable L3.
Closes-Bug: 1654586
Change-Id: Ia2488cb0b752fb4b33f03caa7a1d2469d20395f0
Signed-off-by: Tim Rozet <trozet@redhat.com>