qibuild doc: better help message

Change-Id: I8d937dc6621afe87fb0891c850d8b7455770c996
Reviewed-on: http://gerrit.aldebaran.lan/20979
Reviewed-by: dmerejkowsky <dmerejkowsky@aldebaran-robotics.com>
Tested-by: dmerejkowsky <dmerejkowsky@aldebaran-robotics.com>
Put back `qibuild create` for qibuild2

Change-Id: Ied287841186e39eb008059e34819f41820a02858
Reviewed-on: http://gerrit.aldebaran.lan/20980
Reviewed-by: dmerejkowsky <dmerejkowsky@aldebaran-robotics.com>
Tested-by: dmerejkowsky <dmerejkowsky@aldebaran-robotics.com>