Mizar unit tests show memory leaks for network policy CLI commands.

[vinaykul]

Repro steps:

1. make clean && make all
2. make run_unittests

Expected: All tests pass, no errors.

Actual: Network policy tests fail and show memory leaks..

--------------------------------------------------------------------------------
Test: delete-net-policy-protocol-port-out succeed with well formed policy json input
--------------------------------------------------------------------------------
[  FAILED  ] test_trn_cli_delete_agent_network_policy_protocol_port_subcmd
[==========] 41 test(s) run.
[  PASSED  ] 31 test(s).
[  FAILED  ] 10 test(s), listed below:
[  FAILED  ] test_trn_cli_load_transit_subcmd
[  FAILED  ] test_trn_cli_load_agent_subcmd
[  FAILED  ] test_trn_cli_update_transit_network_policy_subcmd
[  FAILED  ] test_trn_cli_update_agent_network_policy_subcmd
[  FAILED  ] test_trn_cli_delete_transit_network_policy_subcmd
[  FAILED  ] test_trn_cli_delete_agent_network_policy_subcmd
[  FAILED  ] test_trn_cli_update_transit_network_policy_protocol_port_subcmd
[  FAILED  ] test_trn_cli_update_agent_network_policy_protocol_port_subcmd
[  FAILED  ] test_trn_cli_delete_transit_network_policy_protocol_port_subcmd
[  FAILED  ] test_trn_cli_delete_agent_network_policy_protocol_port_subcmd

 10 FAILED TEST(S)

=================================================================
==1912126==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 128 byte(s) in 2 object(s) allocated from:
    #0 0x559076b9f9d5 in __interceptor_malloc (/home/ubuntu/vmizar/build/tests/test_cli+0x289d5)
    #1 0x559076c06722 in cJSON_New_Item src/extern/cJSON.c:214
    #2 0x559076c06722 in cJSON_ParseWithOpts src/extern/cJSON.c:1029
    #3 0x559076c06722 in cJSON_Parse src/extern/cJSON.c:1092
    #4 0x559076be78b7 in trn_cli_parse_json src/cli/trn_cli_common.c:29
    #5 0x559076bf45c7 in trn_cli_delete_transit_pod_and_namespace_label_policy_subcmd src/cli/trn_cli_network_policy.c:981
    #6 0x559076bd2661 in test_trn_cli_delete_transit_pod_and_namespace_label_policy_subcmd src/cli/test/test_cli.c:3032
    #7 0x7f8e80d18c17  (/usr/lib/x86_64-linux-gnu/libcmocka.so.0+0x4c17)

Direct leak of 128 byte(s) in 2 object(s) allocated from:
    #0 0x559076b9f9d5 in __interceptor_malloc (/home/ubuntu/vmizar/build/tests/test_cli+0x289d5)
    #1 0x559076c06722 in cJSON_New_Item src/extern/cJSON.c:214
    #2 0x559076c06722 in cJSON_ParseWithOpts src/extern/cJSON.c:1029
    #3 0x559076c06722 in cJSON_Parse src/extern/cJSON.c:1092
    #4 0x559076be78b7 in trn_cli_parse_json src/cli/trn_cli_common.c:29
    #5 0x559076bf4257 in trn_cli_delete_transit_namespace_label_policy_subcmd src/cli/trn_cli_network_policy.c:927
    #6 0x559076bd28ec in test_trn_cli_delete_transit_namespace_label_policy_subcmd src/cli/test/test_cli.c:2937
    #7 0x7f8e80d18c17  (/usr/lib/x86_64-linux-gnu/libcmocka.so.0+0x4c17)

...

[vinaykul]

This issue is dup of #465.