don't append .config to %LOCALAPPDATA%\<ProgramName>\

::user_config_directory() could use some general cleanup
an x-platform consolidation, but today is not the day.

libs/ardour/filesystem_paths.cc

@@ -70,8 +70,10 @@ user_config_directory ()
 			exit (1);
 		}
 
+#ifndef PLATFORM_WINDOWS
 		p = home_dir;
 		p = Glib::build_filename (p, ".config");
+#endif
 	}
 #endif