[ticket/13161] Avoid problems when running tests with different migrations

PHPBB3-13161
[ticket/13161] Check whether the schema exists, before deleting it

PHPBB3-13161
Merge pull request #3029 from nickvergessen/ticket/13161

Ticket/13161 PHP Warnings issued from phpbb database test case

* nickvergessen/ticket/13161:
  [ticket/13161] Check whether the schema exists, before deleting it
  [ticket/13161] Avoid problems when running tests with different migrations
[ticket/13174] Add missing closing </div> to ucp_pm_viewmessage

PHPBB3-13174
Merge remote-tracking branch 'PayBas/ticket/13174' into develop-ascraeus

* PayBas/ticket/13174:
  [ticket/13174] Add missing closing </div> to ucp_pm_viewmessage
[ticket/13177] Fix display of post count-based ranks in viewtopic.

PHPBB3-13177
Merge pull request #3036 from prototech/ticket/13177

[ticket/13177] Fix display of post count-based ranks in viewtopic.