remove misleading jjb example

Change I059f38d0aa8a8947aaac75e0ddb34d392063ece3 added support for
passing parameters to jobs in groups but not for variable substitution
on those parameters. Substitution on job list parameters would
be a new feature. This change removes a misleading parameter subsitution
example.

Partial-bug: #1298568
Change-Id: I18e28bb622f0473f049963ce6dcf6c4efd11dc2c
Merge "remove misleading jjb example"