px4flow allow delayed background startup

ROMFS/px4fmu_common/init.d/rcS

@@ -405,6 +405,7 @@ else
 			battery_status start
 		fi
 
+		sensors start
 		commander start
 	fi
 
@@ -508,6 +509,12 @@ else
 		gyro_calibration start
 	fi
 
+	# Check for px4flow sensor
+	if param compare -s SENS_EN_PX4FLOW 1
+	then
+		px4flow start -X &
+	fi
+
 	#
 	# Optional board supplied extras: rc.board_extras
 	#