Fix bug 384082 - cppcheck is checking CMake generated files

Summary:
The patch removes cmake generated directory from cppcheck analysis.

BUG: 384082

Test Plan: Works as expected

Reviewers: #kdevelop, kfunk

Reviewed By: #kdevelop, kfunk

Subscribers: kdevelop-devel

Differential Revision: https://phabricator.kde.org/D11041