[ticket/12763] Do not regenerate the *_schema.sql files

PHPBB3-12763
[ticket/12763] Remove empty schema files

PHPBB3-12763
[ticket/12763] Remove invalid comment from oracle and postgres *_schema.sql

PHPBB3-12763
Merge pull request #2643 from nickvergessen/ticket/12763

Ticket/12763 Do not regenerate the *_schema.sql files

* nickvergessen/ticket/12763:
  [ticket/12763] Remove invalid comment from oracle and postgres *_schema.sql
  [ticket/12763] Remove empty schema files
  [ticket/12763] Do not regenerate the *_schema.sql files