Don't fire the wp_enqueue_scripts hook on wp-login.php

[nacin]

admin_enqueue_scripts and wp_enqueue_scripts actions are ideally where wp_enqueue_script() calls should be attached to -- one for the admin, and one for the theme.

[16000] attached wp_enqueue_scripts() to login_head, which is a wrapper function to fire the wp_enqueue_scripts action. This means that a theme attaching a script to the frontend via wp_enqueue_scripts -- even if wrapped in an unnecessary is_admin() check -- will get their JS printed on the login form. This has the potential to throw JS errors, which is what happens in P2 for example.

The fix is to come up with a new action name.

[nacin]

Correcting the admin_enqueue_scripts hook name in the description.

[markjaquith]

(In [17466]) Do not attach wp_enqueue_scripts to login_head. New login_enqueue_scripts hook. props nacin. fixes #16586 for 3.1

[nacin]

[17465] for trunk.