Backup agent changes

backup.py

    def execute_backup(self, context, backup_id, runner=RUNNER):
        ### snip
        ###
        
        runner_opts = CONF.backup_runner_opts
        extra_opts = runner_opts.get(runner.backup_type, '')
        
        try:
            with runner(filename=backup_id,
                        user=user,
                        password=password,
                        extra_opts=extra_opts)\
                    as bkup:
                LOG.info("Starting Backup %s", backup_id)
                success, note, checksum, location = storage.save(
                    bkup.manifest,
                    bkup)
        ##
        ## snip