style++

Summary:
- drop excessive disconnect. when qobjects get destroyed they
  auto-disconnect all their connections, so the explicit disconnect serves
  no purpose
- properly space connect calls

Test Plan: runs and looks to work fine

Reviewers: broulik

Reviewed By: broulik

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D19704