Just return the promise if it's a bg request

This makes the code a bit neater.

src/components/structures/InteractiveAuth.js

@@ -141,26 +141,25 @@ export default React.createClass({
     },
 
     _requestCallback: function(auth, background) {
-        // only set the busy flag if this is a non-background request,
+        const makeRequestPromise = this.props.makeRequest(auth);
-        // otherwise, the user initiated a request, so make the busy
+
-        // spinner appear and clear and existing error messages.
+        // if it's a background request, just do it: we don't want
-        if (!background) {
+        // it to affect the state of our UI.
+        if (background) return makeRequestPromise;
+
+        // otherwise, manage the state of the spinner and error messages
         this.setState({
             busy: true,
             errorText: null,
             stageErrorText: null,
         });
-        }
+        return makeRequestPromise.finally(() => {
-        return this.props.makeRequest(auth).finally(() => {
             if (this._unmounted) {
                 return;
             }
-            // only unset the busy flag if this is a non-background request
-            if (!background) {
             this.setState({
                 busy: false,
             });
-            }
         });
     },