This is what used to happen before the recent refactor to the search UI.
Finishing the main activity means that it never comes back to handle the
"View this app" intent again. Instead, the main Activity just becomes an
entry point for redirecting the UI to the correct place.
Incidentally, I don't particularly like the current solution even though
it should work, and hope to come up with a better one in the future. The
reason is because the behaviour of some methods (`onCreate()` +
`handleIntent()`) is what defines the behaviour of other methods
(`checkForAddRepoIntent()`). This means it is hard to reason about the
state of the activity at any point in time. Developers need to be careful
when making changes to the `onCreate()` method because modifying it has
unintended consequences. That is what caused the problem in issue #541.
Fixes#541.
d23e68be6b