Revert "archlinux: Code cleanups"

This reverts commit 34fd08f87bc2f9340c760721f5e5f728b49297a9.
archlinux: Code cleanups (v2)

Cleanups:
1. Do not modify container's /etc/hosts (archlinux uses /etc/nsswitch.conf)
2. Remove duplicate lines from config
3. Print a nicer final message
4. Get rid of some grep's

Signed-off-by: Leonid Isaev <lisaev@umail.iu.edu>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>