[csw-maintainers] Spam from the pkgrequest form

[William Bonnet]

Hi

I have added a captcha check on the request package form. The form uses 
reCaptcha from code.google.com :)

Feedbacks and comments are welcome. I'll improve slightly the look of 
"error" output on this page during the week end. Tomorrow i'll add the 
maintainer application form.

cheers
W.