Don't attempt to create default repo before config (fixes #530)

We'll create it anyway a little later during startup, as part of the
general "check all repos for viability" step.

cmd/syncthing/main.go

@@ -289,7 +289,6 @@ func main() {
 		l.Infoln("No config file; starting with empty defaults")
 		name, _ := os.Hostname()
 		defaultRepo := filepath.Join(getHomeDir(), "Sync")
-		ensureDir(defaultRepo, 0755)
 
 		cfg, err = config.Load(nil, myID)
 		cfg.Repositories = []config.RepositoryConfiguration{