Issue #2803: fixed a bug for cc.Sprite that its drawing doesn't work when _rect's width or height greater than 0 and less than 1.

Author: dingpinglv

cocos2d/sprite_nodes/CCSprite.js

@@ -2003,11 +2003,11 @@ cc.Sprite = cc.NodeRGBA.extend(/** @lends cc.Sprite# */{
             if (this._colorized) {
                 context.drawImage(image,
                     0, 0, 0 | locRect.width, 0 | locRect.height,
-                    flipXOffset, flipYOffset, locRect.width, locRect.height);
+                    flipXOffset, flipYOffset, 0 | locRect.width, 0 | locRect.height);
             } else {
                 context.drawImage(image,
                     0 | locRect.x, 0 | locRect.y, 0 | locRect.width, 0 | locRect.height,
-                    flipXOffset, flipYOffset, locRect.width, locRect.height);
+                    flipXOffset, flipYOffset, 0 | locRect.width, 0 | locRect.height);
             }
         } else if (locContentSize.width !== 0) {
             var curColor = this.getColor();