ConfigManager: Sync Dolphin settings to SYSCONF on exit

4319 made Dolphin not read/write directly to the SYSCONF and read
settings from the SYSCONF at boot, and only write Dolphin settings
to the SYSCONF at emulation startup.

However, this also made it a bit confusing, because if settings were
changed, then Dolphin was exited without starting a game in between,
the settings wouldn't actually get persisted. This is fixed by
syncing Dolphin settings with the SYSCONF when Dolphin exits.

Source/Core/Core/ConfigManager.cpp

@@ -86,6 +86,7 @@ void SConfig::Shutdown()
 SConfig::~SConfig()
 {
   SaveSettings();
+  SaveSettingsToSysconf();
 }
 
 void SConfig::SaveSettings()