Crash when inspecting return value in console

* Start http_network example
* Press continue
* Run "mkReq()" in console
* Try to inspect the returned ClientResponse object

```
> bugger examples/http_network.coffee
[bugger] Debugging examples/http_network.coffee 
[bugger] chrome-devtools://devtools/devtools.html?ws=127.0.0.1:8058/websocket&toolbarColor=rgba(230,230,230,1)&textColor=rgba(0,0,0,1)
Use mkReq (global) to make requests
Got response: 302

events.js:71
        throw arguments[1]; // Unhandled 'error' event
                       ^
TypeError: Cannot read property 'properties' of undefined
    at module.exports.Runtime.getProperties (/Users/jankrems/Projects/bugger/lib/domains/Runtime.js:196:54)
    at module.exports.fromNativeId (/Users/jankrems/Projects/bugger/lib/debug-client/commands/lookup.js:62:18)
    at unwrapCallback (/Users/jankrems/Projects/bugger/lib/callback-wrapper.js:16:12)
    at EventEmitter.module.exports.parser.on.cache$1 (/Users/jankrems/Projects/bugger/lib/debug-client/index.js:61:12)
    at EventEmitter.emit (events.js:96:17)
    at module.exports.parseBody (/Users/jankrems/Projects/bugger/lib/debug-client/parser.js:41:17)
    at module.exports.parseBuffer (/Users/jankrems/Projects/bugger/lib/debug-client/parser.js:54:89)
    at module.exports.parseBuffer (/Users/jankrems/Projects/bugger/lib/debug-client/parser.js:57:7)
    at Socket.module.exports.debugParser (/Users/jankrems/Projects/bugger/lib/debug-client/parser.js:61:12)
    at Socket.EventEmitter.emit (events.js:96:17)
```