d/control: Don't recommend libnss-gw-name

Closes: Debian bug #1069240
Closes: Debian bug #877935

- libnss-gw-name resolves 'gateway.localhost' to the ip address currently
configured as default route. This has been abandoned upstream[2], deprecated in
Debian[1]. Using libnss-myhostname (part of systemd) instead is recommended[2].

- libnss-gw-name has been removed from testing and unstable. Installing
freedombox package in these distributions no longer installs the libnss-gw-name
package but freedombox installation succeeds as this is only a recommends.
Latest images don't contain the libnss-gw-name package either.

- We already recommend libnss-myhostname and this package is typically installed
along with freedombox package.

- libnss-myhostname resolves '_gateway' where as libnss-gw-name resolves
'gateway.localhost'. This is technically a breaking change. However, we have
neither used nor documented gateway resolution on FreedomBox machines. So, any
disruption is likely minimal.

Tests:

- On a FreedomBox container, running 'ping _gateway' shows that it resolves to
the same IP address as default route shown in 'ip route'.

Links:

1) https://www.debian.org/releases/stable/amd64/release-notes/ch-information.en.html#deprecated-components
2) https://github.com/nomeata/libnss-gw-name

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

debian/control

@@ -160,8 +160,6 @@ Recommends:
  iputils-ping,
 # Manage wireless devices
  iw,
-# Resolve gateway.localhost
- libnss-gw-name,
 # Resolve .local address using mDNS
  libnss-mdns,
 # Resolve current hostname without /etc/hosts