qemu.tests: Update driver install timeout in win_virtio_update

In some guest the install command need longer time to finish. So
make it configurable and set up it an acceptable value.
Also update the cdrom filter string to fit different system,
fix a mistake that use check_cmds in the last step instead op_cmds
and update one error context to make the info log more clear.

Signed-off-by: Yiqiao Pu <ypu@redhat.com>
Merge pull request #1276 from ypu/virtio_win

qemu.tests: Update driver install timeout in win_virtio_update