Move the restart systemdunit function to network manager

Change-Id: I647741fc3976ca82c39998a518b1de7be5365e80
Signed-off-by: Ratan Gupta <ratagupt@linux.vnet.ibm.com>
diff --git a/network_manager_main.cpp b/network_manager_main.cpp
index 2bc203f..dfaeecc 100644
--- a/network_manager_main.cpp
+++ b/network_manager_main.cpp
@@ -46,7 +46,10 @@
 /** @brief restart the systemd networkd. */
 void restartNetwork()
 {
-    restartSystemdUnit("systemd-networkd.service");
+    if (manager)
+    {
+        manager->restartSystemdUnit("systemd-networkd.service");
+    }
 }
 
 void initializeTimers()