virttest: fix login refused when nettype is user

when nettype is 'user' localhost used as hostname by default, and login
windows guest via nc failed; fix it by get hostname/IP address via
socket module;

Signed-off-by: Xu Tian <xutian@redhat.com>
virttest.data_dir: add interface to get deps dir

Signed-off-by: Xu Tian <xutian@redhat.com>
qemu.tests: new case for timedrift testing

changes from V1:
    1. fix typo and update doc strings

Signed-off-by: Xu Tian <xutian@redhat.com>
qemu.tests: configuration for new timedrift testing

changes from v1:
    fix typo and add image_snapshot = no for s4

Signed-off-by: Xu Tian <xutian@redhat.com>
shared.deps: script to adjust host/guest time

Signed-off-by: Xu Tian <xutian@redhat.com>
Merge pull request #1162 from xutian/timedrift_new_case

Timedrift new case