lib MDL-19739 Moved call to include dropdown.js out of outputlib and into the same body of code in weblib

that uses it.
This ensures that it is only loaded if it is used, which is only is the browser is opera, or IE

lib/outputlib.php

@@ -1570,7 +1570,6 @@ class moodle_core_renderer extends moodle_renderer_base {
         $this->page->requires->js('lib/overlib/overlib_cssstyle.js')->in_head();
         $this->page->requires->js('lib/cookies.js')->in_head();
         $this->page->requires->js('lib/ufo.js')->in_head();
-        $this->page->requires->js('lib/dropdown.js')->in_head();
         $this->page->requires->js_function_call('setTimeout', Array('fix_column_widths()', 20));
 
         $focus = $this->page->focuscontrol;

lib/weblib.php

@@ -1172,6 +1172,7 @@ function popup_form($baseurl, $options, $formid, $selected='', $nothing='choose'
         //onfocus will call a function inside dropdown.js. It fixes this IE/Opera behavior.
         //Note: There is a bug on Opera+Linux with the javascript code (first mouse selection is inactive),
         //so we do not fix the Opera behavior on Linux
+        $PAGE->requires->js('lib/dropdown.js')->asap();
         $javascript = ' onfocus="initSelect(\''.$formid.'\','.$targetwindow.')"';
     } else {
         //Other browser