Add modify_image_run_command var to modify-image role

In order to run specific command on the image, we need
to add support for --run-command to the modify image role.
It will be useful to run specific command instead of using
script.

This functionality will be consumed here:
https://review.opendev.org/c/openstack/tripleo-quickstart/+/868864

Related-Bug: #2000226

Signed-off-by: Chandan Kumar <chkumar@redhat.com>
Change-Id: I8575c712467db8fea403459d26731dd7070df131

roles/modify-image/defaults/main.yml

@@ -6,6 +6,12 @@
 # image_to_modify:
 # modify_script:
 
+# Run a specific command
+# modify_image_run_command:
+
+# Note: modify_image_run_command will run first then
+# modify_image_upload_files will run. It is useful in case
+# to make sure remote directories exists.
 # The upload list of files
 modify_image_upload_files: []
 

roles/modify-image/tasks/libguestfs.yml

@@ -23,6 +23,10 @@
   set_fact: _vc_args="{{ _vc_args }} -x"
   when: modify_image_vc_trace|bool
 
+- name: virt-customize agrs --> run command
+  set_fact: _vc_args="{{ _vc_args }} --run-command {{ modify_image_run_command }}"
+  when: modify_image_run_command is defined
+
 - name: virt-customize args --> upload files
   set_fact: _vc_args="{{ _vc_args }} --upload {{ item.src }}:{{ item.dest }}"
   with_items: "{{ modify_image_upload_files }}"