[ticket/13125] $user->browser to $browser

PHPBB3-13125
Merge pull request #3018 from Senky/ticket/13125

[ticket/13125] Uploaded avatars are not displayed

* Senky/ticket/13125:
  [ticket/13125] $user->browser to $browser
Merge pull request #8 from phpbb/develop-ascraeus

follow up changes