Fix NameFormat example

This was testing the wrong thing (double hyphen instead of double
underscore). Fix it to match the description.

Change-Id: I3f5c697ab4f04f86ea7cb576d6d35f4cba9d87a7
Reviewed-on: http://gerrit.causes.com/40964
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>