Old behaviour is that anything that wasn't claimed (or failed to
allocate) would become a SITL RPM sensor. This meant we always had at
least one RPM sensor which was allocated but never provided valid data.
New behaviour is that if you want a SITL RPM sensor you have to set type
to 10.
See discussion here:
https://github.com/ArduPilot/ardupilot/issues/7331
we were getting some uninitialised variables. While it only showed up in
AP_SbusOut, it means we can't be sure it won't happen on other objects,
so safest to remove the approach
Thanks to assistance from Lucas, Peter and Francisco
Peter Barker
Andy Piper
Andrew Tridgell
Randy Mackay
IamPete1
Lucas De Marchi
Mathieu OTHACEHE
Robert Lefebvre