Session#receiveReinvite: flatten promise chain with single '.catch'
Session#receiveReinvite: fail fast if request has no body
Session#receiveReinvite: reduce variable scope
Session#receiveInviteResponse 1xx case: flatten promise chain w/ 1 catch
Session#receiveInviteResponse 2xx case: flatten promise chain w/ 1 catch
test/spec/MediaStreamManager.js: fix indentation