Show indicator when client setup fails (#339)

Summary:
At the moment, when a client is failing to connect, you effectively get an infinite spinner, as it keeps retrying.

This keeps the spinner while it's retrying, but in between, shows a failure icon.

This isn't perfect. It's still shown under possibly the wrong device, but that already happens anyway, this just adds an extra icon.
Pull Request resolved: https://github.com/facebook/flipper/pull/339

Reviewed By: priteshrnandgaonkar

Differential Revision: D13319635

Pulled By: jknoxville

fbshipit-source-id: e16177ecc7058b779fb17b61e20fcbac8ccf0c29

src/reducers/connections.js

@@ -315,7 +315,7 @@ export default function reducer(
           .map(
             c =>
               isEqual(c.client, payload.client)
-                ? {...c, error: errorMessage}
+                ? {...c, errorMessage: errorMessage}
                 : c,
           )
           .sort((a, b) => a.client.appName.localeCompare(b.client.appName)),