FLOATING_IP_POOL is null.

FLOATING_IP_POOL is null.

null no longer works,
the inherited value of public is not being inherited.
rather it is being explicitly set to null.
floating_ip_pool=$(get_cfg "$cfg_file" FLOATING_IP_POOL "null")
This leads me to belive that
get_minion_options function will set the floating_ip
when set explicitly in the minion configs.

Signed-off-by: Aric Gardner <agardner@linuxfoundation.org>
Change-Id: I422ce8f170894329ff8efd54970309cd619e2427