ssh/runcmd(): add if_stdout=False

[Junefen]

Description
When get the libvirt guest ip, sometime it fails with error RTTVAR has grown to over 2.3 seconds, decreasing to 2.0 due to the network delay. Now added a new param if_stdout=False to the runcmd() function, so we can directly get the stdout, which will be the correct ip address.

Test Result - PASS

% python3 -m pytest -v tests/others/test_hypervisors_state.py -k 'libvirt' 
========================================================= test session starts =========================================================
platform darwin -- Python 3.11.2, pytest-7.2.2, pluggy-1.0.0 -- /opt/homebrew/opt/[email protected]/bin/python3.11
cachedir: .pytest_cache
rootdir: /Users/yuefliu/workspace/virtwho-test, configfile: pytest.ini
collected 7 items / 6 deselected / 1 selected                                                                                         

tests/others/test_hypervisors_state.py::TestHypervisorsState::test_state_libvirt PASSED                                         [100%]

================================================== 1 passed, 6 deselected in 21.27s ===================================================

[hkx303]

Good catch