[cogl] buffer: add missing transfer annotations

[Robert Bragg <rbragg src gnome org>]

commit 41a81cc540092a97a571bf3557549deced419e74
Author: Lionel Landwerlin <llandwerlin gmail com>
Date:   Tue Sep 3 16:17:04 2013 +0100

    buffer: add missing transfer annotations
    
    Reviewed-by: Robert Bragg <robert linux intel com>
    
    (cherry picked from commit 84bdd679dfeda837cb080150f1d86daa4b0532ec)

 cogl/cogl-buffer.h |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/cogl/cogl-buffer.h b/cogl/cogl-buffer.h
index 482372a..d160ed0 100644
--- a/cogl/cogl-buffer.h
+++ b/cogl/cogl-buffer.h
@@ -222,7 +222,8 @@ typedef enum { /*< prefix=COGL_BUFFER_MAP_HINT >*/
  * conflicting with the @access mask you pass. It is also an error to
  * release your last reference while the buffer is mapped.
  *
- * Return value: A pointer to the mapped memory or %NULL is the call fails
+ * Return value: (transfer none): A pointer to the mapped memory or
+ *        %NULL is the call fails
  *
  * Since: 1.2
  * Stability: unstable
@@ -259,7 +260,8 @@ cogl_buffer_map (CoglBuffer *buffer,
  * conflicting with the @access mask you pass. It is also an error to
  * release your last reference while the buffer is mapped.
  *
- * Return value: A pointer to the mapped memory or %NULL is the call fails
+ * Return value: (transfer none): A pointer to the mapped memory or
+ *        %NULL is the call fails
  *
  * Since: 2.0
  * Stability: unstable