Fix default fallback for Sublime::View.

Summary:
Fix startup crash of KDevelop by using an existing view instead of a
list index that cannot exist.

Reviewers: KDevelop, kfunk

Reviewed By: KDevelop, kfunk

Subscribers: kfunk, Sergobot, kdevelop-devel

Projects: KDevelop

Differential Revision: https://phabricator.kde.org/D760