In 2.2.1 behavior has changed when network connections are disabled

[paulmelnikow]

After #257 behavior has changed when network connections are disabled. It's emitting this error:

     NetConnectNotAllowedError: Nock: Disallowed net connect for "example.com:80/test"
      at /Users/pnm/code/icedfrisby-nock/node_modules/nock/lib/intercept.js:449:23
      at Object.module.request (node_modules/nock/lib/common.js:99:14)
      at Request.start (node_modules/request/request.js:751:32)
      at Request.end (node_modules/request/request.js:1511:10)
      at end (node_modules/request/request.js:564:14)
      at Immediate.<anonymous> (node_modules/request/request.js:578:7)

Where before the 599 error code was being returned.

I'm not sure if this was intended; needs some more investigation.

See paulmelnikow/icedfrisby-nock#106.