Overview:
If preferred webbrouser is set except Firefox, manual/help pages are not opened due to be passed invalid URL format.

libexo version: exo 0.3.100svn-r29732

Steps to reproduce:
1) Choose preferred web browser except Firefox in "Preferred application" (e.g. Midori)
2) Choose Help -> Contents on any applications (Thunar/Terminal...)

Actual results:
Open error.
--- Message ---
Not found - 'file:///usr/share/xfce4/doc/ja/exo-preferred-applications.html'
--- End ---
* Cause of the error: URL is enclosed by "'".

Additional Information:
* Firefox works correctly.
* In the case of set custom web browser, parameter %s is not parsed correctly if the parameter is enclosed.
 For exmaple:
  kazehakase "%s" -> doesn't work (same reason for above).
  kazehakase %s   -> works correctly. 
* libexo 0.3.100 (stable) works correctly. I confirmed on same system.

Build & Platform:
 Build 2009-04-09 on Arch Linux