Tracker error on delete user

[rgstephens]

When deleting a user, the following Tracker error shows up in the console:

Exception from Tracker recompute function:
debug.js:41 TypeError: Cannot read property 'profile' of undefined
    at singleComposer (single.jsx:13)
    at index.js:221
    at Tracker.Computation._compute (tracker.js:323)
    at Tracker.Computation._recompute (tracker.js:342)
    at Object.Tracker._runFlush (tracker.js:481)
    at Object.Tracker.flush (tracker.js:441)
    at Router._invalidateTracker (router.js:489)
    at afterAllTriggersRan (router.js:101)
    at Object.Triggers.runTriggers (triggers.js:89)
    at route._actionHandle (router.js:105)