variables. (Bug #10351)


mysql-test/r/variables.result:
  Update results
mysql-test/t/variables.test:
  Add regression test
sql/item.h:
  Add Item_uint(ulong) constructor
sql/mysqld.cc:
  Fix default/max max_seeks_for_key to UINT_MAX32
sql/set_var.cc:
  Use correct Item_uint() constructors in sys_var::item()