Removed platform_boot_device_is_image() again; it's now replaced by a field

"booted_from_image" in the kernel_args' boot_disk structure.
Also, added fields "cd" and "user_selected".
A CHOICE_MENU menu can now have a choice text - this is automatically updated
as entries in the menu get selected.
The boot volume menu now has the initial choice text "CD-ROM or hard drive"
in case the boot loader was loaded from an image. The "Rescan volumes" item
is no longer selected by default (only if there was no boot volume found) - but
it's still functionless anyway.
The TAR fs will now appear as "Boot from CD-ROM" in the boot volume menu.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@14388 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/boot/platform.h

@@ -58,7 +58,6 @@ extern status_t platform_add_block_devices(struct stage2_args *args, NodeList *d
 extern status_t platform_get_boot_partition(struct stage2_args *args, Node *bootDevice,
 					NodeList *partitions, boot::Partition **_partition);
 extern status_t platform_register_boot_device(Node *device);
-extern bool platform_boot_device_is_image();
 
 /* menu functions */