THRIFT-5260 Fix the thrift compiler generate problematic lua code for the oneway method
Client: lua
Patch: longzhiri <persistentsnail@gmail.com>

This closes #2212

The oneway method's processor has no need to write the result to client, but it is necessary to return values of each handler's return.
diff --git a/test/lua/test_basic_server.lua b/test/lua/test_basic_server.lua
index acd2d79..20ac407 100644
--- a/test/lua/test_basic_server.lua
+++ b/test/lua/test_basic_server.lua
@@ -66,6 +66,10 @@
   return thing
 end
 
+function TestHandler:testOneway(secondsToSleep)
+  print("testOneway secondsToSleep:", secondsToSleep)
+end
+
 --------------------------------------------------------------------------------
 -- Test
 local server
@@ -132,6 +136,7 @@
     protocolFactory = prot_factory
   }
   assert(server, 'Failed to create server')
+  server:setExceptionHandler(function (err) error(err) end)
 
   -- Serve
   server:serve()