network: change log level when sd_rtnl_message_get_family() returns invalid family (#6923)

From bce67bbee359eec19e6778619b6651100a1c1477, systemd-networkd always shows
```
rtnl: received address with invalid family type 32, ignoring.
```
during boot-up. In the code, there are log_warning() and log_debug() for the
same situation, and the log_debug() is never called. So, let's lower the
log level and remove never called function.

1 files changed, 6 insertions, 3 deletions

diff --git a/src/network/networkd-manager.c b/src/network/networkd-manager.c
index b9cf42d72f..29720a8da0 100644
--- a/src/network/networkd-manager.c
+++ b/src/network/networkd-manager.c
@@ -757,8 +757,11 @@ int manager_rtnl_process_rule(sd_netlink *rtnl, sd_netlink_message *message, voi
         }
 
         r = sd_rtnl_message_get_family(message, &family);
-        if (r < 0 || !IN_SET(family, AF_INET, AF_INET6)) {
-                log_warning_errno(r, "rtnl: received address with invalid family type %u, ignoring.", type);
+        if (r < 0) {
+                log_warning_errno(r, "rtnl: could not get rule family: %m");
+                return 0;
+        } else if (!IN_SET(family, AF_INET, AF_INET6)) {
+                log_debug("rtnl: received address with invalid family %u, ignoring.", family);
                 return 0;
         }
 
@@ -798,7 +801,7 @@ int manager_rtnl_process_rule(sd_netlink *rtnl, sd_netlink_message *message, voi
                 break;
 
         default:
-                log_debug("rtnl: ignoring unsupported rule family: %d", family);
+                assert_not_reached("Received unsupported rule family");
         }
 
         if (from_prefixlen == 0 && to_prefixlen == 0)