Bugfix: Do not create default sync root when loading accounts

Creating the default sync root is only needed at initial setup. If a
user chooses to point all folders for Spaces outside that default sync
root, and deletes the default sync root folder, it will now no longer be
created.

https://github.com/owncloud/client/issues/10919
https://github.com/owncloud/client/pull/11128
