Install command line tools for osx 10.11 and macOS 10.12

Command line tools is needed by homebrew when installing p7zip

Task-number: QTBUG-64729
Change-Id: Ia13838e3f5845351cb682c7d25127c8f36172d3b
Reviewed-by: Liang Qi <liang.qi@qt.io>
Reviewed-by: Jani Heikkinen <jani.heikkinen@qt.io>