Removed dcb->mutex since it didn't solve any problem.

server/include/dcb.h

@@ -134,7 +134,6 @@ typedef struct {
  * gateway may be selected to execute the required actions when a network event occurs.
  */
 typedef struct dcb {
-        simple_mutex_t  mutex;          /**< Protects dcb processing. Coarse and temporary? */
 	int		fd;		/**< The descriptor */
 	int 		state;		/**< Current descriptor state */
 	char		*remote;	/**< Address of remote end */