Option `stop-replay-at-block` exits the app without flushing the database

[only-dev-time]

When steemd is started with the option --replay-blockchain --stop-replay-at-block=99000000, the app will exit without flushing the database.

The next time steemd is started, the database will not contain 99,000,000 blocks:

steem/libraries/plugins/chain/chain_plugin.cpp

Lines 587 to 591 in b2f8567

	if( my->stop_replay_at > 0 && my->stop_replay_at == last_block_number )
	{
	ilog("Stopped blockchain replaying on user request. Last applied block number: ${n}.", ("n", last_block_number));
	exit(EXIT_SUCCESS);
	}