reboot get 500 error when VM is down

When the VM is down, then reboot command is issued, it will get HTTP 500 error since reboot command will firstly issue 'showdown ..' command through IUCV

Here is the log in zvmsdk.log. Besides reboot, other powerVM command also need to be checked.

[2018-06-28 01:24:03] [DEBUG] Get msg to handle: {u'rs': 101, u'overallRC': 2, u'modID': 1, u'rc': 4, u'output': u'', u'errmsg': u"SMUT error: SMUT request failed. RequestData: 'PowerVM DEMOZ01 reboot', Results: '{'rs': 101, 'errno': 0, 'strError': '', 'overallRC': 2, 'rc': 4, 'response': ['(Error) ULTVMU0315E IUCV socket error sending command to DEMOZ01. cmd: shutdown -r now, rc: 4, rs: 101, out: ERROR: ERROR connecting socket:', 'Network is unreachable', 'Return code 4, Reason code 101.']}'"}
[2018-06-28 01:24:03] [INFO] The msg <{u'rs': 101, u'overallRC': 2, u'modID': 1, u'rc': 4, u'output': u'', u'errmsg': u"SMUT error: SMUT request failed. RequestData: 'PowerVM DEMOZ01 reboot', Results: '{'rs': 101, 'errno': 0, 'strError': '', 'overallRC': 2, 'rc': 4, 'response': ['(Error) ULTVMU0315E IUCV socket error sending command to DEMOZ01. cmd: shutdown -r now, rc: 4, rs: 101, out: ERROR: ERROR connecting socket:', 'Network is unreachable', 'Return code 4, Reason code 101.']}'"}> lead to return internal error