videoob: sanitize default download filename
videoob: sanitize default download filename

As full URLs are supported with quvi backend, the default download
filename has to be tweaked.

sputnick-dev/weboob,Boussadia/weboob,frankrousseau/weboob,nojhan/weboob-devel,Konubinix/weboob,laurent-george/weboob,sputnick-dev/weboob,nojhan/weboob-devel,Boussadia/weboob,yannrouillard/weboob,willprice/weboob,RouxRC/weboob,yannrouillard/weboob,laurent-george/weboob,frankrousseau/weboob,RouxRC/weboob,Boussadia/weboob,RouxRC/weboob,frankrousseau/weboob,willprice/weboob,yannrouillard/weboob,willprice/weboob,nojhan/weboob-devel,sputnick-dev/weboob,laurent-george/weboob,Konubinix/weboob,Konubinix/weboob,Boussadia/weboob