[ticket/12990] Use {$var} instead of ${var}

PHPBB3-12990
[ticket/13004] Remove obsolete S_HAS_ATTACHMENTS check from topic tools.

PHPBB3-13004
Merge pull request #2898 from Nicofuma/ticket/12990

[ticket/12990] Use {$var} instead of ${var}
Merge pull request #2900 from prototech/ticket/13004

[ticket/13004] Remove obsolete S_HAS_ATTACHMENTS check from topic tools.

* prototech/ticket/13004:
  [ticket/13004] Remove obsolete S_HAS_ATTACHMENTS check from topic tools.