Non-functional changes.

Remove the unused data type dict_cluster_t.
Remove a bogus comment about latching order.

storage/innobase/include/dict0types.h

@@ -16,11 +16,6 @@ typedef struct dict_index_struct	dict_index_t;
 typedef struct dict_table_struct	dict_table_t;
 typedef struct dict_foreign_struct	dict_foreign_t;
 
-/* A cluster object is a table object with the type field set to
-DICT_CLUSTERED */
-
-typedef dict_table_t			dict_cluster_t;
-
 typedef struct ind_node_struct		ind_node_t;
 typedef struct tab_node_struct		tab_node_t;
 

storage/innobase/include/trx0rseg.h

@@ -121,9 +121,7 @@ struct trx_rseg_struct{
 	ulint		id;	/* rollback segment id == the index of
 				its slot in the trx system file copy */
 	mutex_t		mutex;	/* mutex protecting the fields in this
-				struct except id; NOTE that the latching
-				order must always be kernel mutex ->
-				rseg mutex */
+				struct except id, which is constant */
 	ulint		space;	/* space where the rollback segment is
 				header is placed */
 	ulint		page_no;/* page number of the rollback segment

storage/innodb_plugin/include/dict0types.h

@@ -33,11 +33,6 @@ typedef struct dict_index_struct	dict_index_t;
 typedef struct dict_table_struct	dict_table_t;
 typedef struct dict_foreign_struct	dict_foreign_t;
 
-/* A cluster object is a table object with the type field set to
-DICT_CLUSTERED */
-
-typedef dict_table_t			dict_cluster_t;
-
 typedef struct ind_node_struct		ind_node_t;
 typedef struct tab_node_struct		tab_node_t;
 

storage/innodb_plugin/include/trx0rseg.h

@@ -135,9 +135,7 @@ struct trx_rseg_struct{
 	ulint		id;	/*!< rollback segment id == the index of
 				its slot in the trx system file copy */
 	mutex_t		mutex;	/*!< mutex protecting the fields in this
-				struct except id; NOTE that the latching
-				order must always be kernel mutex ->
-				rseg mutex */
+				struct except id, which is constant */
 	ulint		space;	/*!< space where the rollback segment is
 				header is placed */
 	ulint		zip_size;/* compressed page size of space