fix _last_sent_block_id

[fingera]

Fix sync block
bnet_plugin cannot sync block?
this commit make it work correctly when syncing blocks.
_last_sent_block_id initialized to 0.
I think It's not forked.

eos/plugins/bnet_plugin/bnet_plugin.cpp

Lines 791 to 799 in f9a3d02

	if( nextblock->previous != _last_sent_block_id ) {
	if( !is_known_by_peer( nextblock->previous ) ) {
	_last_sent_block_id = _local_lib_id;
	_last_sent_block_num = _local_lib;
	_state = idle_state;
	maybe_send_next_message();
	return;
	}
	}