setup-desktop: remove consolekit2
consolekit2 was removed last month, ref:
https://git.alpinelinux.org/aports/commit/?id=a2f2d8f15fba
https://git.alpinelinux.org/aports/commit/?id=340ad0e2c5a7
Maybe it's time to remove consolekit2 from setup-desktop.in, as mentioned in https://git.alpinelinux.org/aports/commit/?id=340ad0e2c5a7, mate doesn't seem to need it, mate can work without consolekit2.