Merge mysql.com:/home/svoj/devel/mysql/BUG25712/mysql-5.0-engines

into  mysql.com:/home/svoj/devel/mysql/BUG25712/mysql-5.1-engines

mysys/my_seek.c

@@ -61,7 +61,7 @@ my_off_t my_seek(File fd, my_off_t pos, int whence,
   {
     pthread_mutex_lock(&my_file_info[fd].mutex);
     newpos= lseek(fd, pos, whence);
-    pthread_mutex_lock(&my_file_info[fd].mutex);
+    pthread_mutex_unlock(&my_file_info[fd].mutex);
   }
   else
 #endif