slothfs-gitilesfs: exit on errors.

Change-Id: I5ad6c08e07b36aaa4a5e85fe3ba8b01cf3bc15d1

cmd/slothfs-gitilesfs/main.go

diff --git a/cmd/slothfs-gitilesfs/main.go b/cmd/slothfs-gitilesfs/main.go
index 273b890..2e9bfa1 100644
--- a/cmd/slothfs-gitilesfs/main.go
+++ b/cmd/slothfs-gitilesfs/main.go
@@ -45,12 +45,12 @@
 	mntDir := flag.Arg(0)
 	cache, err := cache.NewCache(*cacheDir, cache.Options{})
 	if err != nil {
-		log.Printf("NewCache: %v", err)
+		log.Fatalf("NewCache: %v", err)
 	}
 
 	service, err := gitiles.NewService(*gitilesOptions)
 	if err != nil {
-		log.Printf("NewService: %v", err)
+		log.Fatalf("NewService: %v", err)
 	}
 
 	repoService := service.NewRepoService(*repo)