Prevent division by zero
Prevent division by zero

If no rules have failed, then the template in "Severity of failed rules"
section has to divide by zero, which causes the width CSS propery to be
NaN. NaN is invalid value for CSS width.  A similar situation is also
for the Rule Results section.

OpenSCAP/openscap,OpenSCAP/openscap,OpenSCAP/openscap,OpenSCAP/openscap,OpenSCAP/openscap,OpenSCAP/openscap