Some suites rely on it and it is also the official new API
for all clustered tests. The "ODL_SYSTEM_IP" is only a
convenience API for running non-clustered tests on a
clustered setup.
Change-Id: I12d948043fdf76a1ee98b811d88f3ccd2ac8762f Signed-off-by: Jozef Behran <jbehran@cisco.com>