Don't force a dependency on nfd

Other compatible forwarders may be used

Change-Id: I0736af1619e3b33ebb7c580928ad9b54f9854f04
diff --git a/repo-ng/debian/control b/repo-ng/debian/control
index 0e1fffc..3a129ec 100644
--- a/repo-ng/debian/control
+++ b/repo-ng/debian/control
@@ -15,7 +15,8 @@
 
 Package: repo-ng
 Architecture: i386 amd64 arm64 armel armhf ppc64el
-Depends: ${shlibs:Depends}, ${misc:Depends}, libndn-cxx, ndnsec
+Depends: ${shlibs:Depends}, ${misc:Depends}, ndnsec
+Suggests: nfd
 Description: next generation of NDN repository
  repo-ng is an implementation of a Named Data Networking data repository with the protocol
  defined on NDN wiki: http://redmine.named-data.net/projects/repo-ng/wiki