autotest: fixed race in MinAltFenceAvoid copter test

Tools/autotest/arducopter.py

@@ -1719,8 +1719,6 @@ class AutoTestCopter(vehicle_test_suite.TestSuite):
     # Also check that the vehicle will not try and ascend too fast when trying to backup from a min alt fence due to avoidance
     def MinAltFenceAvoid(self):
         '''Test Min Alt Fence Avoidance'''
-        self.takeoff(30, mode="LOITER")
-        """Hold loiter position."""
 
         # enable fence, only min altitude
         # No action, rely on avoidance to prevent the breach
@@ -1731,6 +1729,9 @@ class AutoTestCopter(vehicle_test_suite.TestSuite):
             "FENCE_ACTION": 0,
         })
 
+        self.takeoff(30, mode="LOITER")
+        """Hold loiter position."""
+
         # Try and fly past the fence
         self.set_rc(3, 1120)