[tracker] examples: Check tracker_sparql_cursor_next() return value.

[Carlos Garnacho <carlosg src gnome org>]

commit 05f8152a1fe7e8bf20859ba69f35d86ba4674996
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Jan 30 12:09:39 2017 +0100

    examples: Check tracker_sparql_cursor_next() return value.
    
    Coverity ID: 1188420

 examples/libtracker-sparql/class-signal.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
---
diff --git a/examples/libtracker-sparql/class-signal.c b/examples/libtracker-sparql/class-signal.c
index 63fce7b..5fda328 100644
--- a/examples/libtracker-sparql/class-signal.c
+++ b/examples/libtracker-sparql/class-signal.c
@@ -34,10 +34,9 @@ handle_statement (gint subject, gint predicate)
        cursor = tracker_sparql_connection_query (con, query, NULL, NULL);
        g_free (query);
 
-       if (!cursor)
+       if (!cursor || !tracker_sparql_cursor_next (cursor, NULL, NULL))
                return;
 
-       tracker_sparql_cursor_next (cursor, NULL, NULL);
        pred = g_strdup (tracker_sparql_cursor_get_string (cursor, 1, NULL));
        query = g_strdup_printf ("SELECT ?t { <%s> <%s> ?t }",
                                 tracker_sparql_cursor_get_string (cursor, 0, NULL),