fixes related to nim-json-rpc bump

nimbus/nimbus.nim

@@ -234,7 +234,7 @@ proc start(nimbus: NimbusNode, conf: NimbusConf) =
 proc stop*(nimbus: NimbusNode, conf: NimbusConf) {.async, gcsafe.} =
   trace "Graceful shutdown"
   if conf.rpcEnabled:
-    nimbus.rpcServer.stop()
+    await nimbus.rpcServer.stop()
   if conf.wsEnabled:
     nimbus.wsRpcServer.stop()
   if conf.graphqlEnabled:

premix/downloader.nim

@@ -20,8 +20,8 @@ type
 
 proc request*(methodName: string, params: JsonNode): JsonNode =
   var client = newRpcHttpClient()
-  client.httpMethod(MethodPost)
-  waitFor client.connect("127.0.0.1", Port(8545))
+  #client.httpMethod(MethodPost)
+  waitFor client.connect("127.0.0.1", Port(8545), false)
   result = waitFor client.call(methodName, params)
   waitFor client.close()