Ensure checksum error is logged

bundle.go

diff --git a/bundle.go b/bundle.go
index 197aff5..8d03074 100644
--- a/bundle.go
+++ b/bundle.go
@@ -183,6 +183,7 @@
 	checksum := hex.EncodeToString(hashWriter.Sum(nil))
 	if checksum != expectedHash {
 		err = errors.New(fmt.Sprintf("Bad checksum on %s. calculated: %s, given: %s", tempFileName, checksum, expectedHash))
+		log.Error(err.Error())
 		return
 	}