Using the networks endpoint with the wrong netmask may give 500 errors. #516
Description
This is not ideal. Assume 172.16.20.0/22 exists:
$ curl -s -H "Authorization: Token $(cat ~/.mreg-cli_auth_token | cut -d "¤" -f2)" 'https://.../api/v1/networks/172.16.20.0%2f20/used_host_list'
<!doctype html>
<html lang="en">
<head>
<title>Server Error (500)</title>
</head>
<body>
<h1>Server Error (500)</h1><p></p>
</body>
</html>
curl -v -s -H "Authorization: Token $(cat ~/.mreg-cli_auth_token | cut -d "¤" -f2)" 'https://.../api/v1/networks/172.16.20.0%2f22/used_host_list'
{"172.16.20.1", "gateway"}