Bug 15809: Redefine multi_param is CGI < 4.08 is used

Bug 15809: Redefine multi_param is CGI < 4.08 is used

On debian Jessie, the CGI version is >= 4.08
Since this version, the param method raise a warning
"CGI::param called in list context".
Indeed, it can cause vulnerability if called in list context

https://metacpan.org/pod/CGI#Fetching-the-value-or-values-of-a-single-named-parameter
http://blog.gerv.net/2014/10/new-class-of-vulnerability-in-perl-web-applications/

There is a long journey to get rid of these warnings.
First I suggest to redefine the multi_param method when the CGI version
 installed is < 4.08, it will allow us to move the wrong ->param calls to
 ->multi_param without waiting for everybody to upgrade.

The different ways to call these 2 methods are:

my $foo = $cgi->param('foo'); # OK

my @foo = $cgi->param('foo'); # NOK, will raise the warning
my @foo = $cgi->multi_param('foo'); #OK

$template->param( foo => $cgi->param('foo') ); # NOK, will raise the warning
                                               # and vulnerable
$template->param( foo => scalar $cgi->param('foo') ); # OK

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Tested a call to multi_param with CGI < 4.08.
With reference to the comments on Bugzilla, this workaround is arguable,
but provides a base to move to multi_param. If we come up with a better
solution, it should be easy to adjust.

Signed-off-by: Brendan Gallagher brendan@bywatersolutions.com