bug#8003: 23.1; Background of mouse is incorrect

[Huafeng Zhou]

Again. It is found that mouse-color is defined in default-frame-alist as 
following.
(setq default-frame-alist
      (append (list '(foreground-color . "black")
            '(mouse-color . "white")
            '(cursor-color . "black")
            '(width . 120)
            '(height . 50)
       default-frame-alist))
The above 'mouse-color' was effective although the following were defined in 
parallel.
'(mouse ((t (:background "blue" :foreground "black" :box (:line-width 2 :color 
"black" :style released-button) :underline "black")))))
The problem was not there in former version of Emacs such as 21.3.1.