[ONOS-7594] Collect onos-diags when ping fails in SR test and other
minor fixes

Change-Id: I5ed5ab44264f7429bca746daad8c637e02094f41
diff --git a/TestON/tests/USECASE/SegmentRouting/SRDhcprelay/dependencies/SRDhcprelayTest.py b/TestON/tests/USECASE/SegmentRouting/SRDhcprelay/dependencies/SRDhcprelayTest.py
index 1bbb0f9..9693add 100644
--- a/TestON/tests/USECASE/SegmentRouting/SRDhcprelay/dependencies/SRDhcprelayTest.py
+++ b/TestON/tests/USECASE/SegmentRouting/SRDhcprelay/dependencies/SRDhcprelayTest.py
@@ -72,8 +72,4 @@
         run.verifyOnosHostIp( main )
         run.verifyNetworkHostIp( main )
 
-        if hasattr( main, 'Mininet1' ):
-            run.cleanup( main )
-        else:
-            # TODO: disconnect TestON from the physical network
-            pass
+        run.cleanup( main )