Bug 29771: Remove trivial cases

Bug 29771: Remove trivial cases

I squashed the patches because they are too trivial to have a test plan.
Or it is too much work to write the test plan for such trivial cases. I
leave the original commit messages just in case.

Generally, this are all cases in which CGI::param is being called in a
trivially identifiable _list context_. i.e. they are assigned to a
@variable.

I left one case out on purpose: admin/auth_subfields_structure.pl

Paul introduced this:

my @kohafield = ''.$input->param('kohafield');
and then:
my $kohafield = $kohafield[$i];

My intuition says it is forcing scalar context on the first assignment
so the list contains a single element and then inside the loop some
$kohafield assignments should lead to undef, and even warnings. I leave
it for a separate patch because it is not that easy testable and is a
sensible area.

Bug 29771: Remove warning from  acqui/finishreceive.pl

This patch removes a warning that shows when receiving.

To test:
1. Do the acq workflow up to the receive step.
2. Once you choose the items and click on Finish
=> FAIL: There's a warning in the logs
3. Revert receipt
4. Apply this patch
5. Receive
=> SUCCESS: No more warnings
6. Sign off :-D

Bug 29771: Remove warning from svc/members/add_to_list

To test:
1. Run:
   $ tail -f /var/log/koha/kohadev/*-error.log
2. Generate a patron list
3. Perform a patron search that gives you a few
4. Select some, and choose to add them to the list
=> FAIL: The logs show the infamous warn:
CGI::param called in list context from /kohadevbox/koha/svc/members/add_to_list
5. Apply this patch
6. Restart plack and repeat 4
=> SUCCESS: No warn!
7. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>