yum-minimal: set locale.conf and tz in chroot

We should be doing more to ensure initial configuration during
configuration.  Taken from the steps done by [1], here we set
locale.conf and a general timezone.

The only reliable UTF8 locale is en_US.UTF-8; we don't want to use C
locale as it causes havoc with things like python3 and unicode.  We
set locale.conf to this.

For Fedora 24 ensure we install the en_* locales too (this is really a
bug separate to this -- when you log in, by default ssh tries to copy
over your locale env variables, so logging into a F24 system would
result in using invalid locales for the most common en_* cases).

While we are here, setup a timezone link.  It turns out infra puppet
overwrites this later, but at least we have a sane default.

[1] https://www.freedesktop.org/software/systemd/man/systemd-firstboot.html#

Change-Id: Ib8951a97f1772bc5228c682e88628ff53400a923

elements/yum-minimal/root.d/08-yum-chroot

@@ -151,8 +151,8 @@ function _install_pkg_manager {
             # uses to get the minimal-langpack and chooses a
             # random(ish) one that satisfies the locale dependency
             # (rhbz#1349258).  Work-around this by explicitly requring
-            # the minimal pack.
-            _lang_pack="glibc-minimal-langpack"
+            # the minimal and english (for en_US.UTF-8) pack.
+            _lang_pack="glibc-minimal-langpack glibc-langpack-en"
         fi
 
         sudo -E yum -y \
@@ -241,6 +241,13 @@ else
     echo -e "# This file intentionally left blank\n" | \
         sudo tee $TARGET_ROOT/etc/resolv.conf
 
+    # set the most reliable UTF-8 locale
+    echo -e 'LANG="en_US.UTF-8"' | \
+        sudo tee $TARGET_ROOT/etc/locale.conf
+    # default to UTC
+    sudo -E chroot $TARGET_ROOT ln -sf /usr/share/zoneinfo/UTC \
+        /etc/localtime
+
     # cleanup
     # TODO : move this into a exit trap; and reconsider how
     # this integrates with the global exit cleanup path.