tests/avocado: ppc_hv_tests.py set alpine time before setup-alpine

tests/avocado: ppc_hv_tests.py set alpine time before setup-alpine

If the time is wrong, setup-alpine SSL certificate checks can fail.
setup-alpine is used to bring up the network, but it doesn't seem
to to set NTP time before the failing SSL checks. This test has
recently started failing presumably because the default time has
now fallen too far behind.

Fix this by setting time from the host time before running setup-alpine.

Fixes: c9cb496710758 ("tests/avocado: ppc add hypervisor tests")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>