dist/tools/dhcpv6-pd_ia: recognize Debian correctly

[mguetschow]

Contribution description

At least on my system, cat /etc/os-release contains NAME="Debian GNU/Linux" and not just NAME="Debian". This fixes the recognition logic to work in this case, too.

Also removing the platform.linux_distribution() part since that is deprecated since python 3.5 and removed since 3.7: https://docs.python.org/3.5/library/platform.html#platform.linux_distribution

Testing procedure

on Debian without keas installed, compile on master for a board with usb-cdc-ecm:

$ make -C examples/gnrc_border_router BOARD=feather-nrf52840-sense UPLINK=cdc-ecm term
...
Traceback (most recent call last):
  File ".../RIOT/dist/tools/dhcpv6-pd_ia/dhcpv6-pd_ia.py", line 72, in <module>
    main()
  File ".../RIOT/dist/tools/dhcpv6-pd_ia/dhcpv6-pd_ia.py", line 68, in main
    server.run()
  File ".../RIOT/dist/tools/dhcpv6-pd_ia/kea.py", line 110, in run
    self.install()
  File ".../RIOT/dist/tools/dhcpv6-pd_ia/base.py", line 92, in install
    self.installer = pkg.PackageManagerFactory.get_installer()
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ".../RIOT/dist/tools/dhcpv6-pd_ia/pkg/__init__.py", line 50, in get_installer
    return AskToInstall()
           ^^^^^^^^^^^^^^
TypeError: Can't instantiate abstract class AskToInstall with abstract method _install

with this PR:

make -C examples/gnrc_border_router BOARD=feather-nrf52840-sense UPLINK=cdc-ecm term
...
Install package kea-dhcp6? [Y/n] 

Issues/PRs references

Encountered while working on #20192

[riot-ci]

Murdock results

✔️ PASSED

666d429 dist/tools/dhcpv6-pd_ia: recognize Debian correctly

Success	Failures	Total	Runtime
1	0	1	12s

Artifacts

[mguetschow]

Thanks!