Percent change division by zero warnings

[pderksen]

Not sure what caused this but I noticed some division by zero PHP warnings in my server logs on my production site from yesterday (running v0.5.0). Example:

[Mon Oct 10 16:41:20.579279 2016] [:error] [pid 7810] [client 209.136.228.130:20256] PHP Warning: Division by zero in .../wp-content/plugins/edd-metrics/includes/class-edd-metrics-functions.php on line 392, referer: .../wp-admin/edit.php?post_type=download&page=edd_metrics

Somehow the $old_val passed in here was zero?

edd-metrics/includes/class-edd-metrics-functions.php

Lines 383 to 393 in e476ff2

	public static function percent_change($new_val, $old_val) {
	if( empty( $old_val ) )
	return 0;
	// Commas break this equation
	$new_val = str_replace( ',', '', $new_val );
	$old_val = str_replace( ',', '', $old_val );
	return ( ( $new_val - $old_val ) / $old_val ) * 100;
	}

Sorry I can't narrow it down more than that right now.

[scottopolis]

Should hopefully fix ecefd29