core+main: switch to std::thread and thread_local

Change-Id: I892eb7d87639c2b0d24a8ed457b9d32635269216
diff --git a/tests/rib-io-fixture.cpp b/tests/rib-io-fixture.cpp
index 91fc979..8702994 100644
--- a/tests/rib-io-fixture.cpp
+++ b/tests/rib-io-fixture.cpp
@@ -38,7 +38,7 @@
   g_mainIo = &getGlobalIoService();
   setMainIoService(g_mainIo);
 
-  g_ribThread = boost::thread([&] {
+  g_ribThread = std::thread([&] {
     {
       std::lock_guard<std::mutex> lock(m);
       g_ribIo = &getGlobalIoService();