ide: Fix memory leak in ide_register_restart_cb()

ide: Fix memory leak in ide_register_restart_cb()

Fix a memory leak in ide_register_restart_cb() in hw/ide/core.c and add
idebus_unrealize() in hw/ide/qdev.c to have calls to
qemu_del_vm_change_state_handler() to deal with the dangling change
state handler during hot-unplugging ide devices which might lead to a
crash.

Signed-off-by: Ashijeet Acharya <[email protected]>
Reviewed-by: John Snow <[email protected]>
Message-id: 1474995212[email protected]
[Minor whitespace fix --js]
Signed-off-by: John Snow <[email protected]>