Fix backup shard copy paste error

This fixes an issue where the wrong variable was updated with the flag
which was copy pasted originally but no replaced.

vitessio#17923 fixed this on `main` and
`release-22.0`, but that wasn't backported.

This backports only the fixed copy paste.

Fixes vitessio#18045

Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>

Author: dbussink

go/cmd/vtctldclient/command/backups.go

@@ -289,7 +289,7 @@ func init() {
 	BackupShard.Flags().BoolVar(&backupShardOptions.AllowPrimary, "allow-primary", false, "Allow the primary of a shard to be used for the backup. WARNING: If using the builtin backup engine, this will shutdown mysqld on the primary and stop writes for the duration of the backup.")
 	BackupShard.Flags().Int32Var(&backupShardOptions.Concurrency, "concurrency", 4, "Specifies the number of compression/checksum jobs to run simultaneously.")
 	BackupShard.Flags().StringVar(&backupShardOptions.IncrementalFromPos, "incremental-from-pos", "", "Position, or name of backup from which to create an incremental backup. Default: empty. If given, then this backup becomes an incremental backup from given position or given backup. If value is 'auto', this backup will be taken from the last successful backup position.")
-	BackupShard.Flags().BoolVar(&backupOptions.UpgradeSafe, "upgrade-safe", false, "Whether to use innodb_fast_shutdown=0 for the backup so it is safe to use for MySQL upgrades.")
+	BackupShard.Flags().BoolVar(&backupShardOptions.UpgradeSafe, "upgrade-safe", false, "Whether to use innodb_fast_shutdown=0 for the backup so it is safe to use for MySQL upgrades.")
 	Root.AddCommand(BackupShard)
 
 	GetBackups.Flags().Uint32VarP(&getBackupsOptions.Limit, "limit", "l", 0, "Retrieve only the most recent N backups.")