Updating ternary logic for hits/misses graphic

[emerham]

Fixes for issue #60

[mustangxu]

This fix works, pls pull

[PHPGangsta]

It might work, but it doesn't make sense 😄

Why is there (still) an assignment (single "=") in it? Why is it overwriting the content of the variable $stats['get_hits_percent']?

I fixed the issue by adding a second equal-sign:

<?php echo $stats['get_hits_percent'] == ' - ' ? '' : 'y: ' . $stats['get_hits_percent'] . ','; ?>

Now it's a comparison instead of an assignment. I guess that's what's intended here.