qemu.tests: Add a subtest disable_win_update for Windows guests

Sometimes Windows guests OS will automatically install updates
which can result in test timeout and guest be arbitrarily killed.
Therefore Windows OS registry table damanged unfortunately.
This patch will stop update service and delete it from installed.

Signed-off-by: Yolkfull Chow <yzhou@redhat.com>

This patch try to fix all the tab and trailing space problems.

Signed-off-by: Jason Wang <jasowang@redhat.com>

KVM test: Fix the typo in run_disable_win_update.

Signed-off-by: Jason Wang <jasowang@redhat.com>

Change 'int' to be 'float' to fix the bug of ValueError.

Signed-off-by: Yolkfull Chow <yzhou@redhat.com>

subtest disable_win_update: Add param login_timeout for booting guest

Signed-off-by: Yolkfull Chow <yzhou@redhat.com>