[Bug] Cannot get repo owner of a fork repository in news feed and personal public activity

[VillagerTom]

Fork repo shows as (deleted)/reponame in feed list.

When clicking the item, app crashs and
crash log is following:

FATAL EXCEPTION: main
Process: com.gh4a, PID: 10455
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.meisolsson.githubsdk.model.User.login()' on a null object reference
	at com.gh4a.activities.RepositoryActivity.makeIntent(RepositoryActivity.java:56)
	at com.gh4a.activities.RepositoryActivity.makeIntent(RepositoryActivity.java:52)
	at com.gh4a.fragment.EventListFragment.onItemClick(EventListFragment.java:188)
	at com.gh4a.fragment.EventListFragment.onItemClick(EventListFragment.java:88)
	at com.gh4a.adapter.RootAdapter.onClick(RootAdapter.java:271)
	at com.gh4a.adapter.EventAdapter.onClick(EventAdapter.java:118)
	at android.view.View.performClick(View.java:5646)
	at android.view.View$PerformClick.run(View.java:22498)
	at android.os.Handler.handleCallback(Handler.java:751)
	at android.os.Handler.dispatchMessage(Handler.java:95)
	at android.os.Looper.loop(Looper.java:154)
	at android.app.ActivityThread.main(ActivityThread.java:6267)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:793)

[maniac103]

Dupe of #1401.