Add root password option to modify-image role

It can be useful (i.e. in baremetal deployments) to set the root
password on the overcloud image, this commit adds this ability to the
modify-image role.

Change-Id: Idf3ee95745c00fbbdbc3a9df4cc8d3e8ea71b46f

roles/modify-image/README.md

@@ -31,6 +31,8 @@ Role Variables
 * `modify_image_vc_cpu` -- number of CPUs to give the virt-customize VM
 * `modify_image_vc_verbose` -- whether to run virt-customize with verbose flag
 * `modify_image_vc_trace` -- whether to run virt-customize with trace flag
+* `modify_image_vc_root_password` -- password for the root account of the image
+  (useful for baremetal envs)
 
 Example Usage
 -------------

roles/modify-image/defaults/main.yml

@@ -18,8 +18,9 @@ modify_image_install_packages: []
 # By default we use the global working directory for modifying images
 modify_image_working_dir: "{{ working_dir }}"
 
-# ram and cpu are not set by default to take libguestfs defaults by default
+# ram, cpu and root password are not set by default to take libguestfs defaults by default
 # modify_image_vc_ram:
 # modify_image_vc_cpu:
+# modify_image_vc_root_password:
 modify_image_vc_verbose: false
 modify_image_vc_trace: false

roles/modify-image/tasks/main.yml

@@ -42,6 +42,10 @@
   set_fact: _vc_args="{{ _vc_args }} --run {{ modify_script }}"
   when: modify_script is defined
 
+- name: virt-customize args --> root password
+  set_fact: _vc_args="{{ _vc_args }} --root-password password:{{ modify_image_vc_root_password }}"
+  when: modify_image_vc_root_password is defined
+
 - name: Run virt-customize on the provided image
   shell: >
     virt-customize {{ _vc_args }}