MAVLink app: added static of struct vehicle_attitude_setpoint_s att_sp, preserving previous value

[dvorak0]

1d283bf removed 'static' incorrectly making it unable to preserve the value of struct vehicle_attitude_setpoint_s att_sp.

The detail is well explained by the comment above this code:

The tricky part in parsing this message is that the offboard sender can set attitude and thrust using different messages. Eg.: First send set_attitude_target containing the attitude and ignore bits set for everything else and then send set_attitude_target containing the thrust and ignore bits set for everything else.

[AndreasAntener]

@thomasgubler could you take a look? :)
It would be nice to make this a member variable instead of the static declaration.

[thomasgubler]

We have #1983 exactly for this

[dvorak0]

Thanks for your reply. @thomasgubler @AndreasAntener

I checked #1983. It fixed the bug by adding variable. However, it is still not merged. So what I should do is waiting for it?

[AndreasAntener]

Thanks Thomas, I completely forgot that this is not merged yet ;)
@dvorak0 so you did a test with #1983 and are able to fly with this? Because #1983 is only waiting for testers to confirm that it's working, so it would be awesome if you could give it a test in real. Then we can go ahead and merge it.

[dvorak0]

@AndreasAntener I've pulled #1983 locally. During my test(set attitude and thrust through mavros) it works well. Maybe it's time to merge it.

[LorenzMeier]

Ok, thanks for testing. Will apply #1983 then.