Don't print pygments error

Don't print pygments error

Find modules shouldn't print tool errors to the cmake output.
These errors can be confusing because it is unclear whether
the error text applies to cmake or something else. Those
errors should go to log files. In this case logging doesn't
seem necessary. We didn't report the error until
b277931fcf4bc. And that commit claims to just fix a bug and
not increase verbosity. Therefore it was likely an
accidental change.