secondaryDomains are always required

they can still become empty after an update but install and change_location
requires them

part of #809

src/reverseproxy.js

@@ -500,7 +500,7 @@ async function writeAppNginxConfig(app, fqdn, type, bundle) {
         robotsTxtQuoted: null,
         cspQuoted: null,
         hideHeaders: [],
-        proxyAuth: null,
+        proxyAuth: { enabled: false },
         ocsp: await isOcspEnabled(bundle.certFilePath)
     };