Add own node checks before sending ping (#548)

Seems there are two occasions possible where we try to ping the
own local node which causes an assert

- One via the bounding
- One via a received ping, which is strange in the first place but
notice in a stack trace

eth/p2p/kademlia.nim

@@ -443,6 +443,7 @@ proc findNode*(k: KademliaProtocol, nodesSeen: ref HashSet[Node],
 
     var bondedNodes: seq[Future[bool]] = @[]
     for node in candidates:
+      if node != k.thisNode:
         bondedNodes.add(k.bond(node))
 
     await allFutures(bondedNodes)
@@ -602,6 +603,9 @@ proc recvPing*(k: KademliaProtocol, n: Node, msgHash: any)
   k.wire.sendPong(n, msgHash)
 
   if getTime() - k.lastPongReceived(n) > BOND_EXPIRATION:
+    # TODO: It is strange that this would occur, as it means our own node would
+    # have pinged us which should have caused an assert in the first place.
+    if n != k.thisNode:
       let pingId = pingId(n, k.ping(n))
 
       let fut = if pingId in k.pongFutures: