Debugging / fixing the "Must login twice" issue

In circles-ios#100 (closed) the login fails the first time we try, but when we input the same username again, the Matrix Session starts right up without asking for a password.

It turns out that the Session init was failing because a signatures upload request was failing when trying to set up cross-signing. The signatures upload request was failing because we hadn't yet sent the crypto crate's initial set of requests.

This MR fixes the problem by re-adding the code to send the initial crypto requests.