[ticket/13035] Remove empty meta tags

PHPBB3-13035
Merge pull request #2933 from bantu/ticket/13035

[ticket/13035] Remove empty meta tags

* bantu/ticket/13035:
  [ticket/13035] Remove empty meta tags
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/13035] Remove empty meta tags

Conflicts:
	phpBB/styles/subsilver2/template/overall_header.html
	phpBB/styles/subsilver2/template/simple_header.html