THRIFT-575. Allow required fields in function parameters

r665255 was a bit too aggressive.  "optional" was causing confusion,
but there doesn't seem to be any harm in allowing "required".

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@810713 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/compiler/cpp/src/thrifty.yy b/compiler/cpp/src/thrifty.yy
index 8f6e167..00e939c 100644
--- a/compiler/cpp/src/thrifty.yy
+++ b/compiler/cpp/src/thrifty.yy
@@ -902,14 +902,7 @@
 FieldRequiredness:
   tok_required
     {
-      if (g_arglist) {
-        if (g_parse_mode == PROGRAM) {
-          pwarning(1, "required keyword is ignored in argument lists.\n");
-        }
-        $$ = t_field::T_OPT_IN_REQ_OUT;
-      } else {
-        $$ = t_field::T_REQUIRED;
-      }
+      $$ = t_field::T_REQUIRED;
     }
 | tok_optional
     {