qt5-tools: fix bug where QT5_GUI_INCLUDE_DIRS was empty
qt5-tools: fix bug where QT5_GUI_INCLUDE_DIRS was empty

Change-Id: I9cf06399f1e59bcae1bdc7a97cda4695189e656a
Reviewed-on: http://gerrit.aldebaran.lan/60823
Tested-by: gerrit
Reviewed-by: dmerejkowsky <1e4b13000fa8777df4cefd2fd8215187e3deb062@aldebaran-robotics.com>

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