Return error is commit-msg not found on gerrit

Change-Id: Ic565cea49058e8fe7e37a62b7d5812b0fb1c71e3
diff --git a/project/project.go b/project/project.go
index 20d63a0..162dcbd 100644
--- a/project/project.go
+++ b/project/project.go
@@ -2300,6 +2300,9 @@
 					if err != nil {
 						return fmt.Errorf("Error while downloading %q: %v", downloadPath, err)
 					}
+					if response.StatusCode != http.StatusOK {
+						return fmt.Errorf("Error while downloading %q, status code: %d", downloadPath, response.StatusCode)
+					}
 					defer response.Body.Close()
 					if b, err := ioutil.ReadAll(response.Body); err != nil {
 						return fmt.Errorf("Error while downloading %q: %v", downloadPath, err)