The login request parameters shouldn't be wrapped in an `auth` object

[mujx]

According to the spec the login request has the following format

{
  "type": "m.login.password",
  "user": "cheeky_monkey",
  "password": "ilovebananas"
}

but instead we use

{
  "auth": {
      "type": "m.login.password",
      "user": "cheeky_monkey",
      "password": "ilovebananas"
  }
}