roles: docker: Add support for SUSE distributions

Add support for installing Docker on SUSE distributions. The Docker
repository at https://yum.dockerproject.org/repo/main/ does not support
recent openSUSE distributions so the only alternative is to use the
packages from the distro repositories. This however renders the
'docker_version' Ansible variable useless on SUSE.

roles/docker/vars/suse.yml

@@ -0,0 +1,15 @@
+---
+docker_kernel_min_version: '0'
+
+docker_package_info:
+  pkg_mgr: zypper
+  pkgs:
+    - name: docker
+
+docker_repo_key_info:
+  pkg_key: ''
+  repo_keys: []
+
+docker_repo_info:
+  pkg_repo: ''
+  repos: []