Revert "Pin rdopkg to 1.4.0"

This reverts commit 8226fa9.

Reason for revert: rdopkg-1.5.1 has been pushed to pypi where rpmlint is not longer a install mandatory requirement but only optional for rdopkg[lint].

Change-Id: I3f4a7f90295e30bf32fd8bd6196d5135e44c34c1

roles/build-test-packages/tasks/main.yml

@@ -88,15 +88,13 @@
         state: latest
         extra_args: --upgrade
 
-    # FIXME(Chandan): Install rdopkg-1.4.0 as latest one is
-    # breaking the CI due to
-    # https://bugs.launchpad.net/tripleo/+bug/1993343
     - name: Pip install rdopkg
       # noqa 403
       pip:
-        name: rdopkg==1.4.0
+        name: rdopkg
         virtualenv: "{{ build_repo_dir }}/dlrn-venv"
         virtualenv_command: "/usr/bin/{{ python_cmd }} -m venv"
+        state: latest
       when: not dlrn_pre_installed|bool
 
     - name: Pip install DLRN