rsvg_handle_set_base_uri(): Assume that the string is really a URI
rsvg_handle_set_base_uri(): Assume that the string is really a URI

This used to try to distinguish between URIs and path names.  I don't
think this is correct; the function is explicitly named
set_base_uri().

If this turns out to break programs, I'll restore the old behavior.

GNOME/librsvg,GNOME/librsvg,GNOME/librsvg,GNOME/librsvg