Fix statements in for() in tooltips's getAveragePosition.

diff --git a/src/core/core.tooltip.js b/src/core/core.tooltip.js
index 77575b6797f5c96bc7df877ed68f3eb22e943dea..6eb6b3a557a2a6c0d7f44661d8ff3b86f68042ec 100755 (executable)
--- a/src/core/core.tooltip.js
+++ b/src/core/core.tooltip.js
@@ -116,7 +116,7 @@ module.exports = function(Chart) {
 
                var x = 0,
                        y = 0;
-               for (i = 0, len - xPositions.length; i < len; ++i) {
+               for (i = 0; i < xPositions.length; ++i) {
                        x += xPositions[i];
                        y += yPositions[i];
                }