Fix graph line curveness switched from 0.x to 0

src/chart/helper/Line.js

@@ -61,6 +61,10 @@ define(function (require) {
             targetShape.cpx1 = cp1[0];
             targetShape.cpy1 = cp1[1];
         }
+        else {
+            targetShape.cpx1 = NaN;
+            targetShape.cpy1 = NaN;
+        }
     }
 
     function updateSymbolAndLabelBeforeLineUpdate () {

src/chart/helper/LinePath.js

@@ -9,7 +9,7 @@ define(function (require) {
     var bezierCurveProto = graphic.BezierCurve.prototype;
 
     function isLine(shape) {
-        return shape.cpx1 == null || shape.cpy1 == null;
+        return isNaN(+shape.cpx1) || isNaN(+shape.cpy1);
     }
 
     return graphic.extendShape({