Fixes extended test failure and adding tags

Fixes:
   - Changing the Force tags PNOR_BIOS_Code_Update to BIOS_Code_Update
     in test_bios_update.robot
   - Added Tag Network_Nping in extended/test_network_nping.robot
   - Added Tag Network_Nping test_lists/skip_test_extended
   - Added Tag Networkd_Ext in extended/test_netwokd_ext.robot
   - Added 'REST Power On' to boot to OS in 'eSEL Test SetUp'
     in test_esel.robot

Resolves openbmc/openbmc-test-automation#726

Change-Id: Ia9b99ae94e6ac307658ff483a4c00dd2713be35a
Signed-off-by: Sweta Potthuri <spotthur@in.ibm.com>
diff --git a/extended/test_esel.robot b/extended/test_esel.robot
index 2780273..ec54604 100644
--- a/extended/test_esel.robot
+++ b/extended/test_esel.robot
@@ -7,6 +7,7 @@
 Resource            ../lib/utils.robot
 Variables           ../data/variables.py
 Resource            ../lib/utils.robot
+Resource            ../lib/boot_utils.robot
 
 Suite Setup         eSEL Test SetUp
 Suite Teardown      Test Cleanup On Exit
@@ -192,6 +193,9 @@
     Should Not Be Empty
     ...   ${OS_PASSWORD}  msg=You must provide OS host user password.
 
+    # Boot to OS.
+    REST Power On
+
     Login To OS Host  ${OS_HOST}  ${OS_USERNAME}  ${OS_PASSWORD}
     Open Connection And Log In