Clarify in ast_bridge_destroy() about how departable channels must be handled.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/12@401212 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/bridge.h

@@ -409,6 +409,12 @@ static inline void _ast_bridge_unlock(struct ast_bridge *bridge, const char *fil
  * \endcode
  *
  * This destroys a bridge that was previously created.
+ *
+ * \note
+ * While this function will kick all channels out of the bridge, channels that
+ * were added to the bridge using ast_bridge_impart() with the flag
+ * AST_BRIDGE_IMPART_CHAN_DEPARTABLE set must have ast_bridge_depart() called
+ * on them before calling ast_bridge_destroy().
  */
 int ast_bridge_destroy(struct ast_bridge *bridge, int cause);