Add TOST spine failure tests

- Add SRONLReboot
- Add SRstratumRestart
- Refactoring SR Staging functions
- Use Network bench component to send traffic
- Add params file for 2x2 qa pod
- Add saving p4 write requests files

Change-Id: I60e43e2acde8b86cab0e47d62533fcf14937702d
diff --git a/TestON/tests/USECASE/SegmentRouting/SRBridging/dependencies/SRBridgingTest.py b/TestON/tests/USECASE/SegmentRouting/SRBridging/dependencies/SRBridgingTest.py
index bfba8df..be98329 100644
--- a/TestON/tests/USECASE/SegmentRouting/SRBridging/dependencies/SRBridgingTest.py
+++ b/TestON/tests/USECASE/SegmentRouting/SRBridging/dependencies/SRBridgingTest.py
@@ -66,7 +66,7 @@
             run.installOnos( main, skipPackage=skipPackage, cliSleep=5 )
             if main.useBmv2:
                 switchPrefix = main.params[ 'DEPENDENCY' ].get( 'switchPrefix', '' )
-                if switchPrefix is None:
+                if switchPrefix is None or "None":
                     switchPrefix = ''
                 # Translate configuration file from OVS-OFDPA to BMv2 driver
                 translator.bmv2ToOfdpa( main )  # Try to cleanup if switching between switch types
@@ -102,6 +102,8 @@
             run.checkFlows( main, minFlowCount=self.topo[ topology ][ 5 if main.useBmv2 else 4 ] * self.topo[ topology ][ 1 ], sleep=5 )
             if main.useBmv2:
                 switchPrefix = main.params[ 'DEPENDENCY' ].get( 'switchPrefix', '' )
+                if switchPrefix is None or "None":
+                    switchPrefix = ''
                 if switchPrefix is not '' and switchPrefix is not None:
                     switchPrefix += ':'
                 leaf_dpid = [ "device:%sleaf%d" % ( switchPrefix, ls + 1 ) for ls in range( self.topo[ topology ][ 1 ]) ]