add a new service.in

Change-Id: I4248d0c177a76555e6b7ba3f6bae564e7650c461
diff --git a/wscript b/wscript
index 217adbf..601cbfc 100644
--- a/wscript
+++ b/wscript
@@ -109,3 +109,8 @@
             name='ndncert-server.service',
             source='systemd/ndncert-server.service.in',
             target='systemd/ndncert-server.service')
+
+        bld(features='subst',
+            name='ndncert-server.service',
+            source='systemd/ndncert-ca.service.in',
+            target='systemd/ndncert-ca.service')