[ticket/13405] Fix a typo in phpbb/migration/data/v310/style_update_p1.php

PHPBB3-13405
Merge pull request #3204 from rxu/ticket/13405

[ticket/13405] Fix a typo in phpbb/migration/data/v310/style_update_p1.php

* rxu/ticket/13405:
  [ticket/13405] Fix a typo in phpbb/migration/data/v310/style_update_p1.php