Buildbot fixes:

- make sp.test work both with and without query_cache (attempt 2)
- fix compile warning in make_sort_key(), as directed by SergeiG

mysql-test/r/sp.result

@@ -3064,7 +3064,6 @@ select @x|
 @x
 3
 # Restore the old query cache size
-set global query_cache_size = @qcs1|
 delete from t1|
 drop function bug9902|
 drop function if exists bug9102|

mysql-test/t/sp.test

@@ -3762,9 +3762,11 @@ select bug9902() from t1|
 select @x|
 
 --echo # Restore the old query cache size
+--disable_query_log
 if (`select @@have_query_cache='YES'`) {
   set global query_cache_size = @qcs1|
 }
+--enable_query_log
 delete from t1|
 drop function bug9902|