Upgrading PHPUnit to verify that sebastianbergmann/phpunit#1115 fixed ocramius/ProxyManager#140

Depends on
 - [x] sebastianbergmann/phpunit#1115
 - [x] zendframework/zf2#5802
 - [x] zendframework/zf2#5804
 - [x] remove ZF2 version bump once the git subtree split has happened (next zf2 minor release)


See ocramius/ProxyManager#140