Fixed bug #31077.

mysqldump adds the "-- Dump completed on YYYY-MM-DD hh:mm:ss" string
to the end of output if the --comments switch is on.
The only way to suppress this line is to use --skip-comments/--compact
switch.

New switch has been added to the mysqldump client command line:
--dump-date.

For the compatibility with previous releases, by default the --dump-date
is on.
The --dump-date switch forces mysqldump to add date to the
"-- Dump completed on ..." string at the end of output.
The --skip-dump-date switch supresses the output of date string
and uses short form of that commentary: "-- Dump completed".
--skip-comments or --compact switches disable the whole commentary
as usual.


client/client_priv.h:
  Fixed bug #31077.
  New OPT_DUMP_DATE option has been added to implement
  the mysqldump client --dump-date switch.
client/mysqldump.c:
  Fixed bug #31077.
  The opt_dump_date variable has been added to imlements
  the mysqldump cliemt --dump-date switch.
  By default this switch is on (for compatibility with previous
  releases).
  The --dump-date switch forces mysqldump to add date to the
  "-- Dump completed on ..." string at the end of output.
  The --skip-dump-date switch supresses the output of date string
  and uses short form of that commentary: "-- Dump completed".
  --skip-comments or --compact switches disable the whole commentary
  as usual.
mysql-test/t/mysqldump.test:
  Added test case for bug #31077.
mysql-test/r/mysqldump.result:
  Added test case for bug #31077.

client/client_priv.h

@@ -51,5 +51,5 @@ enum options_client
   OPT_TRIGGERS,
   OPT_IGNORE_TABLE,OPT_INSERT_IGNORE,OPT_SHOW_WARNINGS,OPT_DROP_DATABASE,
   OPT_TZ_UTC, OPT_AUTO_CLOSE, OPT_SSL_VERIFY_SERVER_CERT,
-  OPT_DEBUG_INFO, OPT_ERROR_LOG_FILE
+  OPT_DEBUG_INFO, OPT_ERROR_LOG_FILE, OPT_DUMP_DATE
 };