Bug 13201: GetSuggestion takes suggestionid

Bug 13201: GetSuggestion takes suggestionid

Having $ordernumber as the parameter in a function which is
handling suggestions and it is used as a suggestion id is
confusing to the coder and person trying to read the code.
This patch corrects the confusion.

REVISED TEST PLAN
-----------------
1) perldoc C4::Suggestions
   -- notice it says ordernumber for the GetSuggestions example.
2) Ensure you have CPL in your branches table.
3) prove -v t/db_dependent/Suggestions.t
   -- if you have more than 8 itemtypes in your database, two
      tests at the end will fail, but that is not relevant to
      the modified GetSuggestions code.
4) apply patch
5) perldoc C4::Suggestions
   -- notice it is corrected now.
6) prove -v t/db_dependent/Suggestions.t
   -- it should run with the same results as in step 3.
      That is, if you have 8 itemtypes, all pass, otherwise
      those two tests fail.
7) run koha qa test tool

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>