Automation fix for Security menu

Changes:
    - Modified "Establish TCP Connections And Get Connection Failures" keyword
    - Added variable cmd_prefix in lib/protocol_setting_utils.robot

Tested:
    - Ran successfully test_bmc_network_security.robot

Change-Id: I9a0d30c24d17c8f7d491bebd7c4376ae95d25209
Signed-off-by: Megha G N <Megha.G.N@ibm.com>
diff --git a/lib/resource.robot b/lib/resource.robot
index 03e2e66..db0ccab 100755
--- a/lib/resource.robot
+++ b/lib/resource.robot
@@ -101,7 +101,7 @@
 ${ICMP_ECHO_REQUEST}       8
 ${CHANNEL_NUMBER}          1
 ${TCP_PACKETS}             tcp
-${TCP_CONNECT}             tcp-connect
+${TCP_CONNECTION}          tcp-connect
 ${ICMP_NETMASK_REQUEST}    17
 ${REDFISH_INTERFACE}       443
 ${SYN_PACKETS}             SYN