Do not use Util::pow with sqrt

Using bigger precision and passing it to standard precision makes no
sense.

Signed-off-by: Michal Čihař <michal@cihar.com>

libraries/gis/GISPolygon.php

@@ -538,10 +538,7 @@ class GISPolygon extends GISGeometry
 
         // Always keep $epsilon < 1 to go with the reduction logic down here
         $epsilon = 0.1;
-        $denominator = sqrt(
-            Util::pow(($y1 - $y0), 2)
-            + Util::pow(($x0 - $x1), 2)
-        );
+        $denominator = sqrt(pow(($y1 - $y0), 2) + pow(($x0 - $x1), 2));
         $pointA = array();
         $pointB = array();