build: update waf to version 2.0.6

Fix discovered build issues

Change-Id: I9a861c955283c1b20cc5065a4baa22bd7c2ab0c1
diff --git a/tests/wscript b/tests/wscript
index a943f1e..de5a52c 100644
--- a/tests/wscript
+++ b/tests/wscript
@@ -1,7 +1,7 @@
 # -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 
 """
-Copyright (c) 2014-2017,  The University of Memphis
+Copyright (c) 2014-2018,  The University of Memphis
                           Regents of the University of California
 
 This file is part of NLSR (Named-data Link State Routing).
@@ -25,20 +25,13 @@
     if not bld.env['WITH_TESTS']:
         return
 
-    bld(
-        features='cxx',
-        name='unit-tests-main',
-        target='unit-tests-main',
-        source='main.cpp',
-        defines=['BOOST_TEST_MODULE=NLSR Unit Tests'],
-        use='nlsr-objects'
-    )
+    bld.objects(target='unit-test-objects',
+                source=bld.path.ant_glob('**/*.cpp', excl=['main.cpp']),
+                use='nlsr-objects')
 
-    bld.program(
-        target='../unit-tests-nlsr',
-        features='cxx cxxprogram',
-        source=bld.path.ant_glob(['**/*.cpp'], excl=['main.cpp']),
-        use='nlsr-objects unit-tests-main',
-        install_path=None,
-        # defines='TEST_CONFIG_PATH=\"%s/conf-test\"' %(bld.bldnode)
-    )
+    bld.program(target='../unit-tests-nlsr',
+                name='unit-tests-nlsr',
+                source='main.cpp',
+                defines=['BOOST_TEST_MODULE=NLSR Unit Tests'],
+                use='unit-test-objects',
+                install_path=None)