[TIMOB-10565] MobileWeb: TextField - clearing value when focused

The text set by the value property in textField is being cleared when you focus the textField. Also, textField.value does not have the correct value if it was set durring creation.

Steps to repro (text disappearing):

1. run the code below 2. notice the text in the text field 3. click on the text field 4. notice that the text in the field disappears

Steps to repro (value empty):

1. run the code below 2. click anywhere 3. notice the alert dialog pop up, but the textField has no value 4. type in the text field 5. click again 6. notice that the textField now has a value

var win  = Ti.UI.createWindow({
	backgroundColor: 'white'
});
win.open();

var textField = Ti.UI.createTextField({
	height: 50,
	width: 300,
	backgroundColor: 'yellow',
	value: "some text"
});
win.add(textField);

win.addEventListener('click', function(){
	alert('Value: '+textField.value);
});