isUpdating remains true if backgroundReloadAll is false

[wongpeiyi]

See http://emberjs.jsbin.com/xicosasazo/1/edit?html,js,output – click "Click here", then "Go back" –> isUpdating is true even though backgroundReloadAll returns false and no fetch was triggered

Should https://github.com/emberjs/data/blob/03d098d5cdb2fba2249f6c750268240c6400518d/addon/-private/system/store.js#L1378 reset isUpdating to false before returning?

[bmac]

Closed by #4529