coberturalipc.jelly aggregator code needs additional logic to prevent NaN% value (which causes final dashboard jsl to fail)

When I ran dashboard across all my projects, there were several projects where the generated corbetura coverage.xml file did not have the elements that are referenced in coberturalipc.jelly, so it would generate output for that artifact to be: NaN%, which then causes the processing in dashboard.jsl to fail when it sees the %, it assumes its a valid number.

To correct this, I used the attached patch to further verify the result is not NaN before tacking on a % sign, if it is I set the result of 0.

Attached is a patch to fix this issue.