For some unknown reason mac osx does not change NAN to negative in printout
when asking to do so. To get rid of false positive test results change the
sign of NAN to positive, that may break something for someone if there are
people expecting -NAN when devision with zero happens. But that sort of
breakage is pretty unlikely because it requires broken dhcpd.conf.
Signed-off-by: Sami Kerola <kerolasa@iki.fi>