Handle the params in url when calling /ls

[r350178982]

Hi
There is a problem, when I use the LogoutView for loging out the saml sp. Here is the code slice:
django_url:

re_path(r'^org/custom/(?P<org_id>\d+)/saml/', include('djangosaml2.urls')),
when view related to /ls in djangosaml2 is called， there is an error “do_logout_service() got an unexpected arguments "org_id"”, which I guess there is no such arguments in do_logout_service function.

And here is my idea for fixing it:
https://github.com/IdentityPython/djangosaml2/pull/405/files

Please have a look
Thank you.

[peppelinux]

Resolved by #405