Merge pull request #2708 from VisualSJ/develop-ios812

Maybe the black screen of 8.1.3 after adaptation

Author: dingpinglv

cocos2d/core/platform/CCEGLView.js

@@ -58,7 +58,7 @@ cc.__BrowserGetter = {
     adaptationType: cc.sys.browserType
 };
 
-if(window.navigator.userAgent.indexOf("OS 8_1_2") > -1) //this mistake like MIUI, so use of MIUI treatment method
+if(window.navigator.userAgent.indexOf("OS 8_1_") > -1) //this mistake like MIUI, so use of MIUI treatment method
     cc.__BrowserGetter.adaptationType = cc.sys.BROWSER_TYPE_MIUI;
 
 switch(cc.__BrowserGetter.adaptationType){