build: load sanitizers last in wscript to prevent Boost link failure

refs #3828

Change-Id: I582095027dd0330cdad76accd0e2ffe5382840b0
diff --git a/wscript b/wscript
index 767e18c..265f93b 100644
--- a/wscript
+++ b/wscript
@@ -66,8 +66,7 @@
 def configure(conf):
     conf.load(['compiler_cxx', 'gnu_dirs',
                'default-compiler-flags', 'compiler-features', 'type_traits',
-               'pch', 'sanitizers', 'boost', 'boost-kqueue',
-               'dependency-checker', 'websocket',
+               'pch', 'boost', 'boost-kqueue', 'dependency-checker', 'websocket',
                'doxygen', 'sphinx_build'])
 
     conf.find_program('bash', var='BASH')
@@ -154,6 +153,8 @@
 
     conf.load('coverage')
 
+    conf.load('sanitizers')
+
     conf.define('DEFAULT_CONFIG_FILE', '%s/ndn/nfd.conf' % conf.env['SYSCONFDIR'])
 
     # disable assertions in release builds