Pass arguments to changeMaximize in correct order

Summary:
The first argument in AbstractClient::changeMaximize specifies whether
the maximized state of the client needs to be toggled in horizontal
direction.

Reviewers: KWin, romangg

Reviewed By: KWin, romangg

Subscribers: kwin

Tags: KWin

Differential Revision: https://phabricator.kde.org/D22486