Fix "http" monkeypatch

Summary:
Some time ago I had to add a monkeypatch to the `http` library to enforce IPv6, due to the lack of support in Node for that. In version 2.2.0 of `node-fecth`, this has been fixed, and `family: 6` can be enforced via `agent`, which is what this diff does.

I also simplified `Promise` handling at the `test-console-call` level by removing an un-needed `.then()` nesting.

Reviewed By: rafeca

Differential Revision: D9200515

fbshipit-source-id: fe06acddd8e3539f590f88eef3468b02c4242afc

package.json

@@ -177,7 +177,7 @@
     "minimist": "^1.2.0",
     "mkdirp": "^0.5.1",
     "morgan": "^1.9.0",
-    "node-fetch": "^1.3.3",
+    "node-fetch": "^2.2.0",
     "node-notifier": "^5.2.1",
     "npmlog": "^2.0.4",
     "opn": "^3.0.2",