Correct inaccuracy in docker pull documentation

Signed-off-by: Alexander Boyd <alex@opengroove.org>
Cover openSUSE and SUSE Linux Enterprise on the same page

Updated the documentation to cover the installation of Docker on
openSUSE and on SUSE Linux Enterprise.

Docker-DCO-1.1-Signed-off-by: Flavio Castelli <fcastelli@suse.com> (github: flavio)
Merge pull request #9322 from javawizard/patch-1

Correct inaccuracy in docker pull documentation
Merge pull request #9194 from flavio/update_installation_docs

Update installation docs