Fixed SP option selections not being saved

Had forgotten to call prefrences::set_options. Instead of adding an extra call in the
SP Options Manager, I just moved the call to configure_engine::set_options, which is
called by both SP and MP codepaths.

src/game_initialization/configure_engine.cpp

@@ -17,6 +17,7 @@
 #include "game_config_manager.hpp"
 #include "mp_game_settings.hpp"
 #include "preferences/credentials.hpp"
+#include "preferences/game.hpp"
 #include "settings.hpp"
 #include "tod_manager.hpp"
 
@@ -160,6 +161,12 @@ mp_game_settings::RANDOM_FACTION_MODE configure_engine::random_faction_mode_defa
 		preferences::random_faction_mode(), mp_game_settings::RANDOM_FACTION_MODE::DEFAULT);
 }
 
+void configure_engine::set_options(const config& cfg)
+{
+	parameters_.options = cfg;
+	preferences::set_options(cfg);
+}
+
 const config& configure_engine::options_default() const
 {
 	return preferences::options();

src/game_initialization/configure_engine.hpp

@@ -16,7 +16,6 @@
 
 #include "gettext.hpp"
 #include "mp_game_settings.hpp"
-#include "preferences/game.hpp"
 #include "saved_game.hpp"
 
 namespace ng
@@ -241,10 +240,7 @@ class configure_engine
 		parameters_.random_faction_mode = val;
 	}
 
-	void set_options(const config& cfg)
-	{
-		parameters_.options = cfg;
-	}
+	void set_options(const config& cfg);
 
 	//
 	// Parameter defaults

src/gui/dialogs/multiplayer/mp_create_game.cpp

@@ -934,10 +934,7 @@ void mp_create_game::post_show(window& window)
 		prefs::set_random_faction_mode(mp_game_settings::RANDOM_FACTION_MODE::enum_to_string(rfm_types_[selected_rfm_index_]));
 
 		// Save custom option settings
-		const config options_config = options_manager_->get_options_config();
-
-		config_engine_->set_options(options_config);
-		prefs::set_options(options_config);
+		config_engine_->set_options(options_manager_->get_options_config());
 
 		// Set game name
 		const std::string name = find_widget<text_box>(&window, "game_name", false).get_value();