This test assumed that `/sync` would be called immediately after rendering
`<MatrixChat />` but this isn't true in an IndexedDB world: it bounces via
`store.startup()` first.
It looks like the tests resolve this by adding `q.delay(1)` so that's what
I've done: in the future it would be better to extend `HttpBackend` to have
a `waitFor(req) Promise` function so we can removing timing from the tests.
d876e4482b