binary).


mysql-test/r/ps.result:
  Test results fixed (Bug#9379)
mysql-test/t/ps.test:
  A test case for Bug#9379 (collation of a parameter marker is binary)
sql/item.cc:
  - set Item_param::collation to str_value collation, if Item_param
  is assigned a string. Reset it to default in Item_param::reset() (on 
  the next execution it can be assigned a number).
sql/item_func.cc:
  - now that item collation can change between executions
  (if this item is Item_param), we need to register the change
  of the execution tree in the rollback list.