[TIMOB-24399] Android: Fix Ti.UI.WebView.html property setter

[garymathews]

• Fix Titanium.UI.WebView.html property setter
• Remove unnecessary and undocumented optional argument from Titanium.UI.WebView.setHtml

TEST CASE

var win = Ti.UI.createWindow(),
    webView = Ti.UI.createWebView();
 
webView.html = '<h1>Hello</h1>';

win.add(webView);
win.open();

JIRA Ticket

[maggieaxway]

CR FT pass

[mukherjee2]

FR Passed with this environment:
NPM Version: 2.15.9
Node Version: 4.5.0
Mac OS: 10.12.3
Appc CLI: 6.1.0
Appc CLI NPM: 4.2.8
Appcelerator Studio, build: 4.8.1.201612050850
Android Device 6.0.1 and 7.1

I first verified the bug on SDK 6.0.2 The fix is validated with this PR. I am able to see "hello" when installing the app on Android 6 and 7 devices.