message: Retry the request for the master key from SSSS on login
  If this failed we assumed it didn't exist which would erroneously
  prompt people to upgrade encryption.
diff: @@ -1907,13 +1907,19 @@ export default createReactClass({
  }
  // Test for the master cross-signing key in SSSS as a quick proxy for
  - // whether cross-signing has been set up on the account.
  - let masterKeyInStorage = false;
  + // whether cross-signing has been set up on the account. We can't
  + // really continue until we know whether it's there or not so retry
  + // if this fails.
  + let masterKeyInStorage;
  + while (masterKeyInStorage === undefined) {
  try {
  masterKeyInStorage = !!await cli.getAccountDataFromServer("m.cross_signing.master");
  } catch (e) {
  - if (e.errcode !== "M_NOT_FOUND") {
  - console.warn("Secret storage account data check failed", e);
  + if (e.errcode === "M_NOT_FOUND") {
  + masterKeyInStorage = false;
  + } else {
  + console.warn("Secret storage account data check failed: retrying...", e);
  + }
  }
  }
  