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/lib/lua/TServer.lua b/lib/lua/TServer.lua
index 4e37d58..9afe19e 100644
--- a/lib/lua/TServer.lua
+++ b/lib/lua/TServer.lua
@@ -85,9 +85,17 @@
   end
 end
 
+function TServer:setExceptionHandler(exceptionHandler)
+  self.exceptionHandler = exceptionHandler
+end
+
 function TServer:_handleException(err)
   if string.find(err, 'TTransportException') == nil then
-    print(err)
+    if self.exceptionHandler then
+      self.exceptionHandler(err)
+    else
+      print(err)
+    end
   end
 end