upnp/natpmp: register controller only if account is enabled

If UPNP is enabled by the user, the UPNP controller must registered
only if the account is enabled.

Gitlab: #639

Change-Id: I993b50ea37fafa847460650d901ac3c3d5039718

src/account.cpp

@@ -169,13 +169,17 @@ Account::updateUpnpController()
 {
     std::lock_guard<std::mutex> lk {upnp_mtx};
 
-    if (upnpEnabled_ and not upnpCtrl_) {
+    if (not upnpEnabled_ or not isUsable()) {
+        upnpCtrl_.reset();
+        return;
+    }
+
+    // UPNP enabled. Create new controller if needed.
+    if (not upnpCtrl_) {
         upnpCtrl_.reset(new upnp::Controller());
         if (not upnpCtrl_) {
             throw std::runtime_error("Failed to create a UPNP Controller instance!");
         }
-    } else if (not upnpEnabled_) {
-        upnpCtrl_.reset();
     }
 }