remove short array syntax

The short array syntax was introduced in PHP 5.4 and therefore leads
to failing tests when executed in PHP 5.3 environments.
Merge branch '2.3' into 2.5

* 2.3:
  remove short array syntax
  fix session restart on PHP 5.3
Merge branch '2.5' into 2.6

* 2.5:
  remove short array syntax
  fix session restart on PHP 5.3
Merge branch '2.6' into 2.7

* 2.6:
  remove short array syntax
  fix session restart on PHP 5.3
  Avoid missing method when using __invoke