Bug 15747: Do not use CGI->param in list context - Auth.pm

Bug 15747: Do not use CGI->param in list context - Auth.pm

Test plan:
Log you in!
Without this patch applied, you will get a warning
"Fetching the value or values of a single named parameter"
With this patch applied, the warning from C4::Auth line 401 should not
appear anymore in the log file.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Note: no warnings for older CGI versions.

Signed-off-by: Brendan Gallagher brendan@bywatersolutions.com
(cherry picked from commit d9c19c6d45ad3f62119e3a29f37e227f635cb85c)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>