bug#5671: 23.1.92; ffap vs. utf-8 space characters vs. email addresses

[jidanni]

I was wondering why FFAP didn't correctly react to a C-x C-f done upon
the coswas@...com.tw address in http://coswas.org/01coswas/966 .
Well, it is because there are some space characters that FFAP isn't
clear about:
$ echo coswas@....com.tw　　|uni2ascii -qsa P
coswas@....com.twU+3000U+3000

In GNU Emacs 23.1.92.1 (i486-pc-linux-gnu, GTK+ Version 2.18.7)
 of 2010-02-25 on elegiac, modified by Debian
 (emacs-snapshot package, version 1:20100224-1)