Fixed Bug #66762 Segfault in mysqli_stmt::bind_result() when link closed

Each new mysqli_stmt now increase the refcount of the link object.
So the link is really destroy after all statements.

Only implemented with libmysqlclient, as mysqlnd already implement
this internally.

So, libmysqlclient and mysqlnd have the same behavior.
test for bug #66762
NEWS
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  NEWS
  test for bug #66762
  Fixed Bug #66762 Segfault in mysqli_stmt::bind_result() when link closed
NEWS
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  NEWS
  NEWS
  test for bug #66762
  Fixed Bug #66762 Segfault in mysqli_stmt::bind_result() when link closed
NEWS
Merge branch 'PHP-5.6'

* PHP-5.6:
  NEWS
  NEWS
  NEWS
  test for bug #66762
  Fixed Bug #66762 Segfault in mysqli_stmt::bind_result() when link closed