This commit improves engine installation documentation for CentOS,
RHEL, Fedora and Oracle Linux. There are a few fixes and
simplifications. In particular:
1. Fix language about when GPG keys are presented for verification
(when you install a package from a recently added repo).
2. Remove mentions of 'yum/dnf makecache fast'. Unlike Debian/Ubuntu,
which require 'apt update', with both yum and dnf, 'makecache'
is redundand. What's worse, 'dnf makecache fast' is not working
(tested on Fedora 26):
# dnf makecache fast
...
dnf makecache: error: argument timer: invalid choice: 'fast' (choose from 'timer')
3. Source repos are disabled by default, so there is no need to specify
the architecture when running `yum list docker-[ce]e`. The comment
explaining it is also removed.
4. An extra > character in the middle of the line was removed.
[v3: rebase, remove $DOCKERURL reuse hack]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Kirill Kolyshkin
Misty Stanley-Jones