missing after downgrade

Obsolete arc/ directory and view .frm file backup support
has been removed by the patch for bug 17823. However, that
bugfix caused a problem with "live downgrades" of the
server: if we rename some view 4 times under 5.1.29/5.0.72
and then try to rename it under 5.1.28/5.0.70 on the same
database, the server fails with a error:

  query 'RENAME TABLE ... TO ...' failed: 6: Error on
  delete of '....frm-0001' (Errcode: 2)

Also .frm file of that view may be lost (renamed to .frm~).

The server failed because it tried to rename latest 3
backup .frm files renaming the view: the server used an
integer value of the "revision" field of .frm file to
extract those file names. After the fix for bug 17823 those
files were not created/maintained any more, however the
"revision" field was incremented as usual. So, the server
failed renaming non existent files.

This fix solves the problem by removing the support for
"revision" .frm file field:
1. New server silently ignores existent "revision" fields
   in old .frm files and never write it down;
2. Old server assumes, that missing "revision" field in new
   .frm files means default value of 0.
3. Accordingly to the fix for bug 17823 the new server
   drops arc/ directory on alter/rename view, so after
   "live downgrade" old server begins maintenance of the
   arc/ directory from scratch without conflicts with .frm
   files.


sql/parse_file.cc:
  Bug #40021: Renaming view fails, archived .frm for view is
              missing after downgrade
  
  1. static write_parameter(): the old_version parameter
     and the section for FILE_OPTIONS_REV have been re moved.
  2. write_parameter(): the max_versions parameter has been
     removed;
  3. sql_create_definition_file(): removal of dead code;
  4. rename_in_schema_file(): revision and num_view_backups
     parameters and dead code have been removed;
  5. File_parser::parse(): FILE_OPTIONS_REV section has been
     removed.
sql/parse_file.h:
  Bug #40021: Renaming view fails, archived .frm for view is
              missing after downgrade
  
  1. The FILE_OPTIONS_REV constant has been removed.
  2. sql_create_definition_file and rename_in_schema_file
     functions: obsolete versions, revision and
     num_view_backups parameters have been removed.
sql/sql_db.cc:
  Bug #40021: Renaming view fails, archived .frm for view is
              missing after downgrade
  
  Commentary update.
sql/sql_trigger.cc:
  Bug #40021: Renaming view fails, archived .frm for view is
              missing after downgrade
  
  sql_create_definition_file() calls have been updates to
  new parameter lists.
sql/sql_view.cc:
  Bug #40021: Renaming view fails, archived .frm for view is
              missing after downgrade
  
  1. The mysql_create_view function code is used for both
     CREATE VIEW and ALTER queries, but query cache is
     necessary for ALTER command only. Check for a non first
     view revision has been replaced with a direct check for
     ALTER query.
  2. The num_view_backups global constant has been removed.
  3. view_parameters: the "revision" .frm field support has
     been removed.
  4. sql_create_definition_file and rename_in_schema_file
     function calls have been updates to new parameter lists.
sql/table.h:
  Bug #40021: Renaming view fails, archived .frm for view is
              missing after downgrade
  
  TABLE_LIST: the revision field has been removed.