Bug 15810: Make sure the CGI->param is not called in a list context when creating...

Bug 15810: Make sure the CGI->param is not called in a list context when creating private shelves

This patch fixes the following bug:
If OpacAllowPublicListCreation is set to "not allow", the creation of a
private list raises an error at the OPAC.

CGI->param is called in a list context and some parameters are not
filled from the template if the pref is set to "not allow".
To make sure we don't have a "Odd number of elements in anonymous hash",
we force the context to scalar.

Test plan:
1/ Set OpacAllowPublicListCreation to "not allow"
2/ Create private and public lists at the OPAC and the intranet
=> Everything should work fine with this patch applied

Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Brendan Gallagher brendan@bywatersolutions.com
(cherry picked from commit d6329e4f96e46a5e2fbe0ced4d385c42d47e2a84)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>