CMake: Do not try to parse progress information lines

The lines with "[x%] Building something" do not contain errors,
so there is no need to parse them (causing false positives to show
up).

Change-Id: Iee87deb73db9e82040cab5401b74c70be91e6191
Reviewed-by: Alexander Drozdov <adrozdoff@gmail.com>
Reviewed-by: Tim Jenssen <tim.jenssen@theqtcompany.com>