Change time.sleep to wait_until to make sure guest is up. Add guest_reset testcase.
Change time.sleep to wait_until to make sure guest is up.
Add guest_reset testcase.

Change-Id: I5c704ba1f3ada6001d701b31fa08d14e7e022ed6

mfcloud/python-zvm-sdk,mfcloud/python-zvm-sdk,mfcloud/python-zvm-sdk,mfcloud/python-zvm-sdk