Replace resource.txt with resource.robot

Change-Id: I4d2afd35645880e33a31644cd717bbeae55666f0
Signed-off-by: Sandhya Somashekar <sansomas@in.ibm.com>
diff --git a/network/test_network_nping.robot b/network/test_network_nping.robot
index c5c7f20..1dcd064 100644
--- a/network/test_network_nping.robot
+++ b/network/test_network_nping.robot
@@ -1,7 +1,7 @@
 *** Settings ***
 Documentation  Network stack stress tests using "nping" tool.
 
-Resource  ../lib/resource.txt
+Resource  ../lib/resource.robot
 
 Library  OperatingSystem
 Library  String