Description of problem:
Failed to deploy hosted engine with Failed to execute stage 'Misc configuration': expected string or buffer

Version-Release number of selected component (if applicable):
ovirt-hosted-engine-setup-2.3.12-1.el7ev.noarch
rhvm-appliance-4.3-20190828.0.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Deploy hosted engine(in my case GE-6 and GE-4) on RHEL or RHVH-4.3.6-20190828

Actual results:
the following task failed after 120 retries:

17:29:14 TASK [ovirt.hosted_engine_setup : Wait for the host to be up] ******************
17:29:16 FAILED - RETRYING: Wait for the host to be up (120 retries left).
...
...
17:40:49 FAILED - RETRYING: Wait for the host to be up (1 retries left).
17:40:55 fatal: [lynx22.lab.eng.tlv2.redhat.com]: FAILED! => {"ansible_facts": {"ovirt_hosts": [{"address": "lynx22.lab.eng.tlv2.redhat.com", "affinity_labels": [], "auto_numa_status": "unknown", "certificate": {"organization": "lab.eng.tlv2.redhat.com", "subject": "O=lab.eng.tlv2.redhat.com,CN=lynx22.lab.eng.tlv2.redhat.com"}, "cluster": {"affinity_groups": [], "ballooning_enabled": false, "comment": "", "cpu": {"architecture": "undefined", "type": ""}, "cpu_profiles": [], "custom_scheduling_policy_properties": [{"name": "HighUtilization", "value": "80"}, {"name": "CpuOverCommitDurationMinutes", "value": "2"}], "data_center": {"href": "/ovirt-engine/api/datacenters/a9cb23de-6f4f-4cf5-ba1a-a63df03fa096", "id": "a9cb23de-6f4f-4cf5-ba1a-a63df03fa096"}, "description": "", "enabled_features": [], "error_handling": {"on_error": "migrate"}, "external_network_providers": [], "fencing_policy": {"enabled": true, "skip_if_connectivity_broken": {"enabled": false, "threshold": 50}, "skip_if_gluster_bricks_up": false, "skip_if_gluster_quorum_not_met": false, "skip_if_sd_active": {"enabled": false}}, "firewall_type": "firewalld", "gluster_hooks": [], "gluster_service": false, "gluster_volumes": [], "ha_reservation": false, "href": "/ovirt-engine/api/clusters/d968eb18-d0c1-4d60-b2dc-8bec714e8d74", "id": "d968eb18-d0c1-4d60-b2dc-8bec714e8d74", "ksm": {"enabled": false, "merge_across_nodes": true}, "log_max_memory_used_threshold": 95, "log_max_memory_used_threshold_type": "percentage", "mac_pool": {"href": "/ovirt-engine/api/macpools/58ca604b-017d-0374-0220-00000000014e", "id": "58ca604b-017d-0374-0220-00000000014e"}, "memory_policy": {"over_commit": {"percent": 100}, "transparent_huge_pages": {"enabled": false}}, "migration": {"auto_converge": "inherit", "bandwidth": {"assignment_method": "auto"}, "compressed": "inherit"}, "name": "golden_env_mixed_1", "network_filters": [], "networks": [], "permissions": [], "required_rng_sources": ["urandom"], "scheduling_policy": {"href": "/ovirt-engine/api/schedulingpolicies/b4ed2332-a7ac-4d5f-9596-99a439cb2812", "id": "b4ed2332-a7ac-4d5f-9596-99a439cb2812"}, "switch_type": "legacy", "threads_as_cores": false, "trusted_service": false, "tunnel_migration": false, "version": {"major": 4, "minor": 3}, "virt_service": true}, "comment": "", "cpu": {"speed": 0.0, "topology": {}}, "device_passthrough": {"enabled": false}, "devices": [], "external_network_provider_configurations": [], "external_status": "ok", "hardware_information": {"supported_rng_sources": []}, "hooks": [], "href": "/ovirt-engine/api/hosts/7760a9eb-9a6b-4d90-bdfe-b64a201eb678", "id": "7760a9eb-9a6b-4d90-bdfe-b64a201eb678", "katello_errata": [], "kdump_status": "unknown", "ksm": {"enabled": false}, "max_scheduling_memory": 0, "memory": 0, "name": "host_mixed_1", "network_attachments": [], "nics": [], "numa_nodes": [], "numa_supported": false, "os": {"custom_kernel_cmdline": ""}, "permissions": [], "port": 54321, "power_management": {"automatic_pm_enabled": true, "enabled": false, "kdump_detection": true, "pm_proxies": []}, "protocol": "stomp", "se_linux": {}, "spm": {"priority": 5, "status": "none"}, "ssh": {"fingerprint": "SHA256:/J/ONhkgf1whTVtpJMyg1OUbUsV3pp1e8uwQQMIaMVU", "port": 22}, "statistics": [], "status": "install_failed", "storage_connection_extensions": [], "summary": {"total": 0}, "tags": [], "transparent_huge_pages": {"enabled": false}, "type": "rhel", "unmanaged_networks": [], "update_available": false, "vgpu_placement": "consolidated"}]}, "attempts": 120, "changed": false}


in ovirt-engine/host-deploy/ovirt-host-deploy-20190901172917-lynx22.lab.eng.tlv2.redhat.com-2581c74f.log:
2019-09-01 17:29:17,322+0300 DEBUG otopi.plugins.otopi.dialog.machine dialog.__logString:204 DIALOG:SEND       **%EventStart STAGE misc METHOD otopi.plugins.ovirt_host_deploy.kernel.kernel.Plugin._misc (None)
2019-09-01 17:29:17,322+0300 DEBUG otopi.context context._executeMethod:145 method exception
Traceback (most recent call last):
  File "/tmp/ovirt-COJNoXsWHc/pythonlib/otopi/context.py", line 132, in _executeMethod
    method['method']()
  File "/tmp/ovirt-COJNoXsWHc/otopi-plugins/ovirt-host-deploy/kernel/kernel.py", line 185, in _misc
    self._add_disk_uuid_in_fips()
  File "/tmp/ovirt-COJNoXsWHc/otopi-plugins/ovirt-host-deploy/kernel/kernel.py", line 148, in _add_disk_uuid_in_fips
    fips_m = self._RE_FIPS.match(self.environment[e_key])
TypeError: expected string or buffer
2019-09-01 17:29:17,323+0300 ERROR otopi.context context._executeMethod:154 Failed to execute stage 'Misc configuration': expected string or buffer

Expected results:
Deploy successfully

Additional info:
the same we can see in the latest RHVH-4.3.6-20190828