jquery.placeholder: Take placeholder text as parameter

jquery.placeholder: Take placeholder text as parameter

After this change, it will be possible to supply the text to be used as
a placeholder to the plugIn. Instead of doing:
$('<input type="text" />').attr({
        placeholder: "Placeholder text"
}).placeholder();

you can now simply do:
$('input#myInput')
	.placeholder("Placeholder text");

after loading the plug-in.

Bug: 40430
Change-Id: I25255b2ef657f3215e64895d7905b984a1e9d59a