Resolve warning and errors found by latest Google Closure Compiler

[fiskus]

Resolved following issues:

1. Seems like mistyping:

npf/source/npf/pages/request.js:42: WARNING - Variable referenced before declaration: options
  var options = options ? goog.object.clone(this.options) : null;
                ^

2. Google Closure wants {string} for nativeElement.getElementsByTagName, but {enum} for goog.dom.getElementsByTagName:

npf/source/npf/user_agent/css.js:1260: ERROR - actual parameter 1 of Element.prototype.getElementsByTagName does not match formal parameter
found   : goog.dom.TagName<HTMLDivElement>
required: string
        var elems = elem.getElementsByTagName(goog.dom.TagName.DIV);
                                              ^