THRIFT-727 - C++: what() method of generated exceptions will provide more information

Patch: Anna Dymek <aadymek@gmail.com>
Client: C++

This closes #469
diff --git a/tutorial/erl/server.erl b/tutorial/erl/server.erl
index 4915606..f1e7357 100644
--- a/tutorial/erl/server.erl
+++ b/tutorial/erl/server.erl
@@ -44,12 +44,12 @@
         ?tutorial_Operation_MULTIPLY -> Num1 * Num2;
 
         ?tutorial_Operation_DIVIDE when Num2 == 0 ->
-          throw(#invalidOperation{what=Op, why="Cannot divide by 0"});
+          throw(#invalidOperation{whatOp=Op, why="Cannot divide by 0"});
         ?tutorial_Operation_DIVIDE ->
           Num1 div Num2;
 
         _Else ->
-          throw(#invalidOperation{what=Op, why="Invalid operation"})
+          throw(#invalidOperation{whatOp=Op, why="Invalid operation"})
     end.
 
 getStruct(Key) ->