[ticket/12468] Having mbstring.http_input set to '' is as good as 'pass'.

PHPBB3-12468
Merge remote-tracking branch 'github-bantu/ticket/12468' into develop-olympus

* github-bantu/ticket/12468:
  [ticket/12468] Having mbstring.http_input set to '' is as good as 'pass'.
Merge branch 'develop-olympus' into develop-ascraeus

* develop-olympus:
  [ticket/12468] Having mbstring.http_input set to '' is as good as 'pass'.
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/12468] Having mbstring.http_input set to '' is as good as 'pass'.