Add a blank baremetal_hosts file and skip_tags options

Baremetal jobs usinga vrt undercloud need to
ters down previous vm set ups.

A blanks hosts file is needs as the virthost and vm
will be defined in the job.

Change-Id: I0f5194c5d01a991fec010163f1cfe18548132c74

roles/common/vars/main.yaml

@@ -5,6 +5,12 @@ tripleo_quickstart_dir: "{{ ansible_user_dir }}/{{ zuul.projects['git.openstack.
 vxlan_vars: "-e toci_vxlan_networking='false' -e vxlan_networking='false'"
 extra_vars: ""
 job_featureset_file: "{{ tripleo_quickstart_dir }}/config/general_config/featureset{{ featureset }}.yml"
+skip_tags_list: >-
+  {% if environment_type == 'baremetal' -%}
+  tripleo-validations
+  {%- else -%}
+  tripleo-validations,teardown-all
+  {%- endif -%}
 
 featureset_conf: >-
   {% if common_featureset is defined -%}

roles/run-test/templates/toci_quickstart.sh.j2

@@ -17,7 +17,7 @@ export DEFAULT_ARGS="--extra-vars local_working_dir=$LOCAL_WORKING_DIR \
     --inventory $LOCAL_WORKING_DIR/hosts \
     --extra-vars tripleo_root={{ tripleo_root }} \
     --extra-vars working_dir=$WORKING_DIR \
-    --skip-tags "tripleo-validations,teardown-all" \
+    --skip-tags "{{ skip_tags_list }}" \
 "
 
 # --install-deps arguments installs deps and then quits, no other arguments are