[gnome-software/gnome-3-20] trivial: Fix a possible crash spotted by clang

[Kalev Lember <klember src gnome org>]

commit d4730427508740f70b89f8417fc2db01a3918736
Author: Richard Hughes <richard hughsie com>
Date:   Fri Apr 22 18:25:34 2016 +0100

    trivial: Fix a possible crash spotted by clang

 src/gs-shell-details.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gs-shell-details.c b/src/gs-shell-details.c
index 7e1982f..57e0aa9 100644
--- a/src/gs-shell-details.c
+++ b/src/gs-shell-details.c
@@ -996,7 +996,7 @@ gs_shell_details_review_button_clicked_cb (GsReviewRow *row,
 static void
 gs_shell_details_refresh_reviews (GsShellDetails *self)
 {
-       GArray *review_ratings;
+       GArray *review_ratings = NULL;
        GPtrArray *reviews;
        gboolean show_review_button = TRUE;
        gboolean show_reviews = FALSE;