[gtksourceview] Make sure to NULL terminate text for unowned buffers

[Jesse van den Kieboom <jessevdk src gnome org>]

commit 3e30d95e74b191c12cfa28bbf7d6116cc15313dd
Author: Jesse van den Kieboom <jessevdk gmail com>
Date:   Wed Aug 27 14:32:44 2014 +0200

    Make sure to NULL terminate text for unowned buffers
    
    This fixes the case where the stream gets passed in a valid buffer
    (i.e. unowned) which we cannot know is null terminated or not.

 gtksourceview/gtksourcebufferoutputstream.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtksourceview/gtksourcebufferoutputstream.c b/gtksourceview/gtksourcebufferoutputstream.c
index 6511d32..a71e4e7 100644
--- a/gtksourceview/gtksourcebufferoutputstream.c
+++ b/gtksourceview/gtksourcebufferoutputstream.c
@@ -653,7 +653,7 @@ validate_and_insert (GtkSourceBufferOutputStream *stream,
 
                        apply_error_tag (stream);
 
-                       if (nvalid != len && buffer[nvalid] != '\0')
+                       if ((nvalid != len || !owned) && buffer[nvalid] != '\0')
                        {
                                /* make sure the buffer is always properly null
                                 * terminated. This is needed, at least for now,