consistent and explicit use of constant for devp2p protocol version

libp2p/Host.cpp

@@ -709,7 +709,7 @@ bytes Host::saveNetwork() const
 	}
 
 	RLPStream ret(3);
-	ret << c_protocolVersion << m_alias.secret();
+	ret << dev::p2p::c_protocolVersion << m_alias.secret();
 	ret.appendList(count).appendRaw(network.out(), count);
 	return ret.out();
 }
@@ -722,7 +722,7 @@ void Host::restoreNetwork(bytesConstRef _b)
 
 	RecursiveGuard l(x_sessions);
 	RLP r(_b);
-	if (r.itemCount() > 0 && r[0].isInt() && r[0].toInt<unsigned>() == c_protocolVersion)
+	if (r.itemCount() > 0 && r[0].isInt() && r[0].toInt<unsigned>() == dev::p2p::c_protocolVersion)
 	{
 		// r[0] = version
 		// r[1] = key

libp2p/NodeTable.cpp

@@ -477,7 +477,7 @@ void NodeTable::onReceived(UDPSocketFace*, bi::udp::endpoint const& _from, bytes
 			case PingNode::type:
 			{
 				PingNode in = PingNode::fromBytesConstRef(_from, rlpBytes);
-				if (in.version != c_protocolVersion)
+				if (in.version != dev::p2p::c_protocolVersion)
 				{
 					if (auto n = nodeEntry(nodeid))
 						dropNode(n);

libp2p/NodeTable.h

@@ -316,7 +316,7 @@ struct PingNode: RLPXDatagram<PingNode>
 
 	static const uint8_t type = 1;
 
-	unsigned version = c_protocolVersion;
+	unsigned version = dev::p2p::c_protocolVersion;
 	std::string ipAddress;
 	unsigned port;
 	unsigned expiration;