qibuild.project.sdk_directory becomes a property
qibuild.project.sdk_directory becomes a property

Change-Id: I166ab9c7f0b50c84f387bb5ccab2aabaea1d7635
Reviewed-on: http://gerrit.aldebaran.lan:8080/12673
Tested-by: gerrit
Reviewed-by: ncornu <13ba26b8f12d26c819f48749c65f2f7f5c1d13db@aldebaran-robotics.com>

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