message: Fix spurious failures in bipdersig.py
  Run in single threaded mode.
diff: @@ -15,9 +15,9 @@ class BIP66Test(BitcoinTestFramework):
  def setup_network(self):
  self.nodes = []
  - self.nodes.append(start_node(0, self.options.tmpdir, []))
  - self.nodes.append(start_node(1, self.options.tmpdir, ["-blockversion=2"]))
  - self.nodes.append(start_node(2, self.options.tmpdir, ["-blockversion=3"]))
  + self.nodes.append(start_node(0, self.options.tmpdir, ["-net.msgHandlerThreads=1", "-net.txAdmissionThreads=1"]))
  + self.nodes.append(start_node(1, self.options.tmpdir, ["-net.msgHandlerThreads=1", "-net.txAdmissionThreads=1", "-blockversion=2"]))
  + self.nodes.append(start_node(2, self.options.tmpdir, ["-net.msgHandlerThreads=1", "-net.txAdmissionThreads=1", "-blockversion=3"]))
  connect_nodes(self.nodes[1], 0)
  connect_nodes(self.nodes[2], 0)
  self.is_network_split = False
  