general.cmake: cleanup, set cmake_minimum_required
general.cmake: cleanup, set cmake_minimum_required

Change-Id: I5a5093fef3ffecbf021606ce39c36e34f7ae38e3
Reviewed-on: http://gerrit.aldebaran.lan/56178
Reviewed-by: dmerejkowsky <1e4b13000fa8777df4cefd2fd8215187e3deb062@aldebaran-robotics.com>
Tested-by: dmerejkowsky <1e4b13000fa8777df4cefd2fd8215187e3deb062@aldebaran-robotics.com>

aldebaran/qibuild,aldebaran/qibuild,aldebaran/qibuild,aldebaran/qibuild