Return iSCSI IQN from a Linux host.

def _linux_iqn():
    '''
    Return iSCSI IQN from a Linux host.
    '''
    ret = []

    initiator = '/etc/iscsi/initiatorname.iscsi'
    try:
        with salt.utils.files.fopen(initiator, 'r') as _iscsi:
            for line in _iscsi:
                line = line.strip()
                if line.startswith('InitiatorName='):
                    ret.append(line.split('=', 1)[1])
    except IOError as ex:
        if ex.errno != errno.ENOENT:
            log.debug("Error while accessing '%s': %s", initiator, ex)

    return ret