Bug 11219: make CAS authentication work with URL parameters

Bug 10029 tries to fix the use of URL parameters in CAS authentication.
But is does not work.
The full URL must be used in all methods of C4::Auth_with_cas.
Also, in checkpw_cas(), the 'ticket' parameter must be removed to find
the original URL.

This patch removes the 'ticket' parameter from query before calling
checkpw_cas() since the ticket is passed as method arguemnt.
In C4::Auth_with_cas, many methods use the same code to get the CAS
handler and the service URI. This patch adds a private method
_get_cas_and_service() to do the job.

Test plan:
- Enable CAS
- Go to opac without been logged-in
- Try to place hold on a record
=> You get to /cgi-bin/koha/opac-reserve.pl?biblionumber=XXX showing
   authentication page
=> Check that CAS link contains query param "biblionumber"
- Click on CAS link and log in
=> Check you return well logged-in to reserve page with biblionumber
   param
- Check CAS loggout
- Check Proxy CAS auth

Signed-off-by: Koha team AMU <koha.aixmarseille@gmail.com>

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Passes all tests in t, xt, and t/db_dependent/Auth.t.
Also passes QA script.

As I have no working CAS server, I focused on regression testing:
Activated Persona and casAuthentication.
- Verified normal login against database still works.
- Verified Persona login works.
  Note: With Persona you are always forwarded to the patron
  account - so you have to search for the record again before
  you can place a hold.
- Verified that the CAS URL contains the biblionumber when
  logging in while placing a hold.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Retested 2014-04-12

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit c8a18f5eefd81dc07512faa962064effdfb88de9)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
Bug 11219: (follow-up) fetch only URL parameters

This followup corrects the fact that when using $query->url(), both
GET and POST params are get.
Using $query->url_param() will only get params directly in URL.

Test plan :
- Enable CAS
- Go to login page : cgi-bin/koha/opac-user.pl
- Try to connect with local login using random login and password
  (they will be transmitted by POST)
- You stay to login page
- Look at CAS login URL
=> Without this patch it will contain the random login and password
   as parameters of opac-user.pl
=> With this patch it does not contain any parameter

Signed-off-by: Matthias Meusburger <matthias.meusburger@biblibre.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit b57d98517c5a9572a54412f7f4e5d872acfa85c3)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>