[ticket/13042] Remove unused variables

PHPBB3-13042
Merge pull request #2940 from Senky/ticket/13042

[ticket/13042] Unused var in login_box()

* Senky/ticket/13042:
  [ticket/13042] Remove unused variables
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/13042] Remove unused variables