Bug 6840 warning in logs

Bug 6840 warning in logs

In staff interface, in search (catalogue/search.pl), there is a warning saying:
[Fri Sep  2 18:20:24 2011] search.pl: Use of uninitialized value $key in hash
element at /home/paul/koha.dev/koha-community/C4/Templates.pm line 227.

The problem happens when searching from the quick search toolbar, not when you
search from advanced search.
Investigating, it seems it's because the sort_by is not defined in this case.

This patch
* fixes the problem in Search.pl by setting the parameter only if there is a sort_by field
* modify te Template->param sub to get a better error message. Instead of having just "use of uninitia..." get the value you try to set to an empty key. Much easier to understand which line causes the problem

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Ian Walls <ian.walls@bywatersolutions.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>