Throws unhandled rejection (Callback was already called)

[mikberg]

Thanks for an awesome mixin!

I'm getting unhandled rejections when deleting stuff, and have tracked it down to this line, which may both return a promise and call the callback.

2. Unhandled Rejection
   Error: Callback was already called.
    /Users/mikael/.../node_modules/strong-remoting/node_modules/async/dist/async.js:844:36
    /Users/mikael/.../node_modules/strong-remoting/node_modules/async/dist/async.js:3676:17
    /Users/mikael/.../node_modules/strong-remoting/node_modules/async/dist/async.js:339:31
    interceptInvocationErrors (/Users/mikael/.../node_modules/strong-remoting/lib/remote-objects.js:690:22)
    /Users/mikael/.../node_modules/loopback-phase/node_modules/async/lib/async.js:154:25
    /Users/mikael/.../node_modules/loopback-phase/node_modules/async/lib/async.js:154:25
    /Users/mikael/.../node_modules/loopback-phase/node_modules/async/lib/async.js:154:25
    /Users/mikael/.../node_modules/strong-remoting/lib/remote-objects.js:656:7
    /Users/mikael/.../node_modules/strong-remoting/lib/http-context.js:397:7
    /Users/mikael/.../node_modules/strong-remoting/lib/shared-method.js:270:11
    process._tickDomainCallback (internal/process/next_tick.js:129:7)

Removing the return keyword from the line fixes the error.