xend: solve issues with xm block-configure command.
In the case of inactive managed domains:
The following error occurs currently. We cannot change the
configuration of the VBD by using xm block-configure. Of course,
using xm block-detach and xm block-attach instead of xm
block-configure, we can change it. However, I'd like to change it by
using xm block-configure.
In the case of active domains:
Another problem occurs after a domain was rebooted. Even if we
change a configuration of a VBD in the domain by using xm
block-configure, the configuration of the VBD is reverted to previous
configuration after the domain was rebooted.
Signed-off-by: Masaki Kanno <kanno.masaki@jp.fujitsu.com>