Update and delete registration with account reuse (#6174)

* find the correct url when deactivating an acmev1 account on the acmev2 endpoint

* set regr in ClientNetwork.account after deactivating on the server

* update self.net.account

* move logic into update_registration

* return methods to their original order to please git

* factor out common code

* update test_fowarding to use a method that still gets forwarded

* add acme module test coverage

* pragma no cover on correct line

* use previous regr uri

* strip unnecessary items from regr before saving

* add explanation to main.py

* add extra check to client_test.py

* use empty dict instead of empty string to indicate lack of body that we save to disk

certbot/main.py

@@ -735,8 +735,13 @@ def register(config, unused_plugins):
     cb_client = client.Client(config, acc, None, None, acme=acme)
     # We rely on an exception to interrupt this process if it didn't work.
     acc_contacts = ['mailto:' + email for email in config.email.split(',')]
+    prev_regr_uri = acc.regr.uri
     acc.regr = cb_client.acme.update_registration(acc.regr.update(
         body=acc.regr.body.update(contact=acc_contacts)))
+    # A v1 account being used as a v2 account will result in changing the uri to
+    # the v2 uri. Since it's the same object on disk, put it back to the v1 uri
+    # so that we can also continue to use the account object with acmev1.
+    acc.regr = acc.regr.update(uri=prev_regr_uri)
     account_storage.save_regr(acc, cb_client.acme)
     eff.handle_subscription(config)
     add_msg("Your e-mail address was updated to {0}.".format(config.email))