[rhythmbox] ext-db: fix crash when store request processing fails

[Jonathan Matthew <jmatthew src gnome org>]

commit 5d18adbc170538170b7cc388f20d3e0cb2119fd2
Author: gkrithi8 <gkrithi8 gmail com>
Date:   Mon Nov 27 13:31:39 2017 +0530

    ext-db: fix crash when store request processing fails
    
    https://bugzilla.gnome.org/show_bug.cgi?id=727670

 metadata/rb-ext-db.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/metadata/rb-ext-db.c b/metadata/rb-ext-db.c
index 3e241e6..7d8e015 100644
--- a/metadata/rb-ext-db.c
+++ b/metadata/rb-ext-db.c
@@ -954,7 +954,11 @@ do_store_request (GSimpleAsyncResult *result, GObject *object, GCancellable *can
                 */
                g_signal_emit (store, signals[STORE], 0, req->value, &req->data);
 
-               rb_debug ("stored value into encoded data of type %s", G_VALUE_TYPE_NAME (req->data));
+               if (req->data != NULL) {
+                       rb_debug ("stored value into encoded data of type %s", G_VALUE_TYPE_NAME (req->data));
+               } else {
+                       rb_debug ("failed to store value");
+               }
        } else {
                /* indicates we actually didn't get anything, as opposed to communication errors etc.
                 * providers just shouldn't call rb_ext_db_store_* in that case.