Gallery: Fix problem with sub-sub directory with special chars

Hi, 
i thought i had fixed #155 in gallery

but in fact no /o\ 
here is an example path that make it fail ..

/bëßt grétîng/Müller Frank/myphoto.jpg

....

my patch try to avoid this double encoding problem. 

i feared that it will break other things in the gallery with some browsers like ie & cie