Thrift: Fix a bug with local reflection and namespaces.

Thrift: Fix a bug with local reflection and namespaces.

Summary:
References to "local reflections" in other thrift files were not given
namespace prefixes, give undefined symbol errors.  This change
distinguishes between relfection names being generated for declarations
(not namespaced) and those that could be external references (namespaced).

Reviewed By: mcslee

Test Plan:
Got the following files to build and link correctly with -dense.

==> test1.thrift <==
cpp_namespace ns
enum foo { bar }

==> test2.thrift <==
include "test1.thrift"
enum dummy_enum_workaround { I_AM_A_WORKAROUND }
struct baz {
  1: test1.foo qux
}

Revert Plan: ok

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665472 13f79535-47bb-0310-9956-ffa450edef68