Ensure DIB is installed from source

Bifrost clones the DIB repo and installs it. However, after running
install.yaml pip freeze shows diskimage-builder 2.33 is installed.

This is caused by the recent addition of IPA builder, which has its own
dependency on diskimage-builder.

This change fixes the issue by swapping the order of installation of IPA
builder and DIB, to ensure DIB is installed last.

Change-Id: Ifd67adaa98e920f42c80d239349ae61d7d610f66
Story: 2007401
Task: 38999
(cherry picked from commit d878f65eea)

playbooks/roles/bifrost-ironic-install/tasks/install.yml

@@ -54,13 +54,6 @@
   environment: "{{ venv }}"
   when: skip_install is not defined
 
-- name: "Diskimage-builder - Install"
-  include: pip_install.yml
-    package=diskimage-builder
-    sourcedir={{ dib_git_folder }}
-    source_install=true
-  when: skip_install is not defined and install_dib | bool == true
-
 - name: "IPA-builder - Install"
   include: pip_install.yml
     package=ironic-python-agent-builder
@@ -68,6 +61,15 @@
     source_install=true
   when: skip_install is not defined and install_dib | bool == true
 
+# NOTE(mgoddard): IPA-builder has a dependency on diskimage-builder. Install
+# DIB last to ensure it is installed from source rather than PyPI.
+- name: "Diskimage-builder - Install"
+  include: pip_install.yml
+    package=diskimage-builder
+    sourcedir={{ dib_git_folder }}
+    source_install=true
+  when: skip_install is not defined and install_dib | bool == true
+
 - name: "sushy - Install"
   include: pip_install.yml
     package=sushy