ArduPlane v3.7.0 - Sends mavlink messages with two different system ids

[DonLakeFlyer]

Issue details

Steps:

• Flash ArduPlane 3.7.0 to Pixhawk
• Boot QGC (with Pixhawk disconnected)
• Connect Pixhawk to QGC via USB

Result:
ArduPlane sends mavlink messages with sysid of 7 and 1. 1 is the correct system id. This causes QGC to think there are two different vehicles connected and shows all it's multi-vehicle ui. Pretty bad bug for any groundstation that supports multiple vehicles. The mavlink messages with id 7 are sent first during board boot I believe, then it switches to 1.

Here is QGC mavlink inspector showing the messages:

[DonLakeFlyer]

ArduCopter 3.3 doesn't do this. ArduPlane didn't used to do this in older versions.

[mboland]

Arducopter does this in 3.4, QGroundControl and Mission Planner

[tridge]

thanks for letting me know, I'll fix this now

[rmackay9]

I tried to set this to Copter-3.4 milestone but github doesn't accept two milestones so resetting to plane only.

[KIrill-ka]

As a workaround, I set MAV sysid to 7 :)

[DonLakeFlyer]

Ah, thanks for the suggestion! Helpful for my testing.

[OXINARF]

Fixed in master.

[rmackay9]

Oh, excellent that it's fixed!