add email sending script

refs: #4053
Change-Id: I1ffe550b20e7fe394fb7f25d71eafa61d4a8fc6f
diff --git a/wscript b/wscript
index 2f86766..438b03f 100644
--- a/wscript
+++ b/wscript
@@ -91,6 +91,15 @@
 
     bld.install_files("${SYSCONFDIR}/ndncert", "client.conf.sample")
 
+    bld.install_files("${SYSCONFDIR}/ndncert", "ndncert-mail.conf.sample")
+
+    bld(features="subst",
+        source='ndncert-send-email-challenge.py',
+        target='ndncert-send-email-challenge',
+        install_path="${BINDIR}",
+        chmod=Utils.O755,
+       )
+
     bld(features = "subst",
         source='libndn-cert.pc.in',
         target='libndn-cert.pc',