tools: switch to Face::getIoContext()

Change-Id: I6be4c682d62e1061af45052d2141b9e5b9e897c5
diff --git a/tests/tools/ndn-autoconfig-server/program.t.cpp b/tests/tools/ndn-autoconfig-server/program.t.cpp
index ee99740..cf81b7b 100644
--- a/tests/tools/ndn-autoconfig-server/program.t.cpp
+++ b/tests/tools/ndn-autoconfig-server/program.t.cpp
@@ -88,7 +88,7 @@
   }
   this->initialize(options);
 
-  DummyClientFace clientFace(face.getIoService());
+  DummyClientFace clientFace(face.getIoContext());
   clientFace.linkTo(face);
 
   Name baseName("/localhop/nfd/rib/routable-prefixes");