summary: fix test flake

[daywalker90]

          wait_for(lambda: l1.rpc.listpeers(l2id)["peers"][0]["connected"] is False)
          l1.daemon.wait_for_log("Peerstate wrote to datastore")
          time.sleep(1)
          s2 = l1.rpc.summary()

          # then
          avail1 = int(re.search(" ([0-9]*)% ", s1["channels"][2]).group(1))
          avail2 = int(re.search(" ([0-9]*)% ", s2["channels"][2]).group(1))
  >       assert avail1 == 100
  E       assert 50 == 100