[ticket/12474] Error messages should be displayed with <error> tag

PHPBB3-12474
[ticket/12475] Error in db:update console command

PHPBB3-12475
Merge pull request #2380 from Nicofuma/ticket/12474

[ticket/12474] The console command for updating/migrating the db should display the error with the <error> tag

* Nicofuma/ticket/12474:
  [ticket/12474] Error messages should be displayed with <error> tag
Merge pull request #2381 from Nicofuma/ticket/12475

[ticket/12475] Undefined variable $log in db:migrate console command

* Nicofuma/ticket/12475:
  [ticket/12475] Error in db:update console command