Assert and log total_home

I have a theory total_home (only set on shard0's service) could be ran
using a service from another shard, but on shard0. We should add
assertions and logs for what total_allowance is because that's what the
stacktrace reported as crashing.

src/v/net/conn_quota.cc

@@ -454,8 +454,11 @@ void conn_quota::do_put(ss::net::inet_address addr) {
 
     auto home_shard = addr_to_shard(addr);
     if (home_shard == ss::this_shard_id()) {
-        vlog(rpc::rpclog.trace, "do_put: release directly to home");
         auto allowance = get_home_allowance(addr);
+        vlog(
+          rpc::rpclog.trace,
+          "do_put: release directly to home allowance={}",
+          allowance);
         allowance->put();
         if (should_leave_reclaim(*allowance)) {
             cancel_reclaim_to(addr, allowance);