Deprecation warning on disable-ticketing

Using:
```shell
[ale@flo vms]$ qemu-img --version
qemu-img version 7.0.0 (Debian 1:7.0+dfsg-7ubuntu2)
Copyright (c) 2003-2022 Fabrice Bellard and the QEMU Project developers
```
I see:
```shell
qemu-system-x86_64: -spice port=5924,disable-ticketing: warning: short-form boolean option 'disable-ticketing' deprecated                             
Please use disable-ticketing=on instead
```