Add new qemu block format support in cdrom v3

Change log to v2:
1. add new function process_info_block() to deal with the new style qemu info blcok.

In qemu monitor, 'info block' has changed, the old style is:
info block
scsi0-hd0: removable=0 io-status=ok file=
./autotest/client/tests/virt/shared/data/images/f18-64.qcow2 ro=0 drv=qcow2 encrypted=0 bps=0 bps_rd=0 bps_wr=0 iops=0 iops_rd=0 iops_wr=0
scsi0-cd1: removable=1 locked=1 tray-open=0 io-status=ok file=./autotest/client/tests/virt/shared/data/images/orig.iso ro=1 drv=raw encrypted=0 bps=0 bps_rd=0 bps_wr=0 iops=0 iops_rd=0 iops_wr=0

But the in new qemu with the commit id:
fbe2e26
info block
drive-virtio-disk1: ./autotest/client/tests/virt/shared/data/images/f18-64.qcow2 (qcow2)

drive-ide0-0-0: ./autotest/client/tests/virt/shared/data/images/orig.iso (raw, read-only)
Removable device: locked, tray closed

This two patches, make autotest to support the new qemu .
Signed-off-by: Mike Qiu qiudayu@linux.vnet.ibm.com