Need using namespace boost in thrift threads test

Reviewed By: jake luciani


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665119 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/test/cpp/src/main.cpp b/test/cpp/src/main.cpp
index 235f21a..f048027 100644
--- a/test/cpp/src/main.cpp
+++ b/test/cpp/src/main.cpp
@@ -26,6 +26,7 @@
 using __gnu_cxx::hash;
 
 using namespace std;
+using namespace boost;
 
 using namespace facebook::thrift;
 using namespace facebook::thrift::protocol;