migrate to dhtnet namespace

Change-Id: I7143a010bd83e8cfa7a3c8c3072ed23f6f0ba8e3
diff --git a/include/tls_session.h b/include/tls_session.h
index 4a4b994..19db4fc 100644
--- a/include/tls_session.h
+++ b/include/tls_session.h
@@ -46,7 +46,7 @@
 } // namespace crypto
 } // namespace dht
 
-namespace jami {
+namespace dhtnet {
 namespace tls {
 
 enum class TlsSessionState {