Purchases: unsubscribed state still active after renewal

[fabianapsimoes]

Reported by @TheSteveK.

The unsubscribed state noticed is still displayed after renewal, for a short moment. This shouldn't happen as renewals resubscribe unsubscribed products.

Steps to reproduce:

• Go to /purchases and select an unsubscribed product.
• You'll see the unsubscribed state notice, prompting users to renew.
• Click Renew Now and complete checkout.
• You'll be redirected back to Manage Purchase. Note that the unsubscribed state notice is still there, though it disappears in a few seconds once the information about the subscription is updated.

Before:

After:

Related to 11802-gh-calypso-pre-oss (cc @andreabadgley who also noted this back then).

[scruffian]

This can probably be fixed together with #189.

[drewblaisdell]

The current solution for #189 is to replace the currently saved purchase object with a new one returned by the cancel-private-registration endpoint, so this will probably need to be fixed in a separate PR.

Unless anyone has a better one, I think a realistic solution for v1 is just to display the entire ManagePurchase placeholder state until we've fetched the purchases again.