[tracker] cli: Fix potentially uninitialised variable

[Sam Thursfield <sthursfield src gnome org>]

commit 346a5c293f47371499b7ab9ce36ca06fe7cb7386
Author: Sam Thursfield <sam afuera me uk>
Date:   Tue Jun 23 00:05:09 2020 +0200

    cli: Fix potentially uninitialised variable

 src/tracker/tracker-export.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/tracker/tracker-export.c b/src/tracker/tracker-export.c
index a6a50e9af..095fdf0cc 100644
--- a/src/tracker/tracker-export.c
+++ b/src/tracker/tracker-export.c
@@ -184,7 +184,7 @@ print_trig (TrackerSparqlCursor *cursor,
        gchar *predicate;
        gchar *object;
        gchar *previous_graph = NULL;
-       const gchar *graph;
+       const gchar *graph = NULL;
 
        while (tracker_sparql_cursor_next (cursor, NULL, NULL)) {
                graph = tracker_sparql_cursor_get_string (cursor, 0, NULL);