Fix OpenStack clients region parameter

"load_balancer.region" option description contains "If empty, the value
of identity.region is used instead", but the initialization code doesn't
use identity.region at all.
This commit adds a fallback to identity.region if load_balancer.region
is empty or undefined.

Change-Id: Ia7c53ba57f01d63ad76e42d0417d0547cf827026
1 file changed