Fix policy forward command

Change-Id: I3030279b4e77c19f2a764555d21a30246ed3628b
diff --git a/tcp_tests/managers/runtestmanager.py b/tcp_tests/managers/runtestmanager.py
index b0e7c38..d340cbc 100644
--- a/tcp_tests/managers/runtestmanager.py
+++ b/tcp_tests/managers/runtestmanager.py
@@ -144,7 +144,7 @@
                 'description': ("Enable packets forwarding"),
                 'node_name': self.target_name,
                 'cmd': ("set -ex;" +
-                        salt_call_cmd + "iptables --policy FORWARD ACCEPT")
+                        "iptables --policy FORWARD ACCEPT")
             }
         ]
         if not pipeline: