Define interfaces of NetworkManager

Change-Id: Ia696c382b0b7cbf5980f17e0d64ed4d286db25cb
Signed-off-by: Ratan Gupta <ratagupt@in.ibm.com>
diff --git a/Makefile.am b/Makefile.am
index 9c341d8..6f95786 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -6,7 +6,8 @@
 netman_watch_dns_CFLAGS = $(SYSTEMD_CFLAGS)
 
 noinst_HEADERS = \
-		ethernet_interface.hpp
+		ethernet_interface.hpp \
+		network_manager.hpp
 
 phosphor_network_manager_SOURCES = \
 		ethernet_interface.cpp \