As a SWHID with qualifiers might have some percent encoded characters (like ;
which is used as separator between qualifiers) and HTTP servers will unquote
received URL arguments, a SWHID must also be percent encoded when used as an
URL argument.
This prevent HTTP errors when trying to browse such SWHIDs as previously the
unquoting performed by HTTP servers would remove percent encoding of qualifiers
and thus break escaping of ; used ad separation character.