qt: fix for cmake 2.8.9
qt: fix for cmake 2.8.9

Change-Id: I0541d1ceecd64c534ad2480250ec18e0b7bce487
Reviewed-on: http://gerrit.aldebaran.lan:8080/10819
Reviewed-by: dmerejkowsky <1e4b13000fa8777df4cefd2fd8215187e3deb062@aldebaran-robotics.com>
Tested-by: dmerejkowsky <1e4b13000fa8777df4cefd2fd8215187e3deb062@aldebaran-robotics.com>

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