made rpc.call less flimsy hopefully

lib/rpc.lua

@@ -37,8 +37,8 @@ function rpc.call(hostname,fn,...)
  local rt = {}
  repeat
   local _, from, port, data = event.pull(30, "net_msg", hostname, rpc.port)
-  rt = serial.unserialize(data) or {}
- until rt[1] == rv or computer.uptime() > st + 30
+  rt = serial.unserialize(tostring(data)) or {}
+ until (type(rt) == "table" and rt[1] == rv) or computer.uptime() > st + 30
  if table.remove(rt,1) == rv then
   return table.unpack(rt)
  end