tc: Correct json output for actions

tc: Correct json output for actions

Commit 9fd3f0b255d9 ("tc: enable json output for actions") added JSON
support for tc-actions at the expense of breaking other use cases that
reach tc_print_action(), as the latter don't expect the 'actions' array
to be a new object.

Consider the following taken duringrun of tc_chain.sh selftest,
and see the latter command output is broken:

$ ./tc/tc -j -p actions list action gact | grep -C 3 actions
[ {
        "total acts": 1
    },{
        "actions": [ {
                "order": 0,

$ ./tc/tc -p -j -s filter show dev enp3s0np2 ingress | grep -C 3 actions
            },
            "skip_hw": true,
            "not_in_hw": true,{
                "actions": [ {
                        "order": 1,
                        "kind": "gact",
                        "control_action": {

Relocate the open/close of the JSON object to declare the object only
for the case that needs it.

Signed-off-by: Yuval Mintz <yuvalm@mellanox.com>
Tested-by: Roman Mashak <mrv@mojatatu.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>