More fixes for Python 3 compatibility (#13008)

* More fixes for Python 3 compatibility

* Workaround if the six module is not pip installed

* Lose the semicolons

integrationtests/python_src/px4_it/mavros/mavros_offboard_attctl_test.py

@@ -46,6 +46,7 @@ from geometry_msgs.msg import Quaternion, Vector3
 from mavros_msgs.msg import AttitudeTarget
 from mavros_test_common import MavrosTestCommon
 from pymavlink import mavutil
+from six.moves import xrange
 from std_msgs.msg import Header
 from threading import Thread
 from tf.transformations import quaternion_from_euler

integrationtests/python_src/px4_it/mavros/mavros_offboard_posctl_test.py

@@ -47,6 +47,7 @@ import numpy as np
 from geometry_msgs.msg import PoseStamped, Quaternion
 from mavros_test_common import MavrosTestCommon
 from pymavlink import mavutil
+from six.moves import xrange
 from std_msgs.msg import Header
 from threading import Thread
 from tf.transformations import quaternion_from_euler

integrationtests/python_src/px4_it/mavros/mavros_test_common.py

@@ -11,6 +11,7 @@ from mavros_msgs.srv import CommandBool, ParamGet, SetMode, WaypointClear, \
                             WaypointPush
 from pymavlink import mavutil
 from sensor_msgs.msg import NavSatFix
+from six.moves import xrange
 
 
 class MavrosTestCommon(unittest.TestCase):

integrationtests/python_src/px4_it/mavros/mission_test.py

@@ -53,6 +53,7 @@ from mavros import mavlink
 from mavros_msgs.msg import Mavlink, Waypoint, WaypointReached
 from mavros_test_common import MavrosTestCommon
 from pymavlink import mavutil
+from six.moves import xrange
 from threading import Thread