[librsvg] test-display: Fix potential g_object_unref(NULL) call

[Philip Withnall <pwithnall src gnome org>]

commit 6f6be8c524cc42828eb87c10b54a242c6a2484e3
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Fri Nov 29 12:55:23 2013 +0000

    test-display: Fix potential g_object_unref(NULL) call
    
    base_file can legitimately be NULL at this point.
    
    Found by scan-build.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=719552

 test-display.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/test-display.c b/test-display.c
index 7223126..4b8929b 100644
--- a/test-display.c
+++ b/test-display.c
@@ -752,7 +752,8 @@ main (int argc, char **argv)
                                                     RSVG_HANDLE_FLAGS_NONE,
                                                     NULL /* cancellable */,
                                                     &err);
-    g_object_unref (base_file);
+    if (base_file != NULL)
+        g_object_unref (base_file);
     g_object_unref (input);
 
     if (info.handle == NULL) {