Fix exercise 'binding triggers to actions' due api changes

[jumapico]

Fix due changes in the api.

Using client 2017-07-12T20:09:28+00:00:

$ wsk rule update first-trigger-rule rule-trigger first-trigger-action
ok: updated rule first-trigger-rule
$ wsk rule get first-trigger-rule
ok: got rule first-trigger-rule
{
    "namespace": "---",
    "name": "first-trigger-rule",
    "version": "0.0.1",
    "status": "active",
    "trigger": {
        "name": "rule-trigger",
        "path": "---"
    },
    "action": {
        "name": "first-trigger-action",
        "path": "---"
    },
    "publish": false
}

[jthomas]

Thanks for fixing this @jumapico! If you catch anything else, please keep the PRs coming.... 💯.

@csantanapr @rabbah - can you merge please?

[jthomas]

Published to NPM @ 0.1.2