Do not set value to 0 and do not add rows without non-zero value.
Also fix javascript in template to avoid coloring 'No items to display.'
With the following rules:
$ openstack congress policy rule create action 'warning(x) :- blah(x)'
$ openstack congress policy rule create classification 'blah(x) :- error(x)'
Monitoring pane pre-patch shows rows of zero warning/error
screenshot: https://imagebin.ca/v/3VXCVtZxXYUQ
rows suppressed post-patch.
screenshot: https://imagebin.ca/v/3VXX9g34QOGf
Closes-Bug: 1708294
Change-Id: I56adc4da430e3e1e15bd31c42fe3f7bce996dcd0
becbd719cd