Firefly: drop D gain

ROMFS/px4fmu_common/init.d/13002_firefly6

@@ -14,12 +14,12 @@ then
 	param set MC_ROLL_P 7.0
 	param set MC_ROLLRATE_P 0.17
 	param set MC_ROLLRATE_I 0.002
-	param set MC_ROLLRATE_D 0.004
+	param set MC_ROLLRATE_D 0.003
 	param set MC_ROLLRATE_FF 0.0
 	param set MC_PITCH_P 7.0
 	param set MC_PITCHRATE_P 0.14
 	param set MC_PITCHRATE_I 0.002
-	param set MC_PITCHRATE_D 0.004
+	param set MC_PITCHRATE_D 0.003
 	param set MC_PITCHRATE_FF 0.0
 	param set MC_YAW_P 3.8
 	param set MC_YAW_FF 0.5