motd-news only works with one URL even though docs say mutiple URLs can be configured

[Prasad]

The motd-news script etc/update-motd/50-motd-news
the following section

```
# Loop over any configured URLs
for u in $URLS; do
        # Ensure https:// protocol, for security reasons
        case $u in
                https://*)
                        true
                ;;
                https://motd.ubuntu.com)
                        u="$u/$codename/$arch"
                ;;
                *)
                        continue
                ;;
        esac
        # If we're forced, set the wait to much higher (1 minute)
        [ "$FORCED" = "1" ] && WAIT=60
        # Fetch and print the news motd
        if curl --connect-timeout "$WAIT" --max-time "$WAIT" -A "$USER_AGENT" -o- "$u" >"$NEWS" 2>"$ERR"; then
                echo
                # At most, 10 lines of text, remove control characters, print at most 80 characters per line
                safe_print "$NEWS"
                # Try to update the cache
                safe_print "$NEWS" 2>/dev/null >$CACHE || true
        else
                : > "$CACHE"
        fi
done

```

As you can see the $CACHE gets overwritten if multiple URLs are configured in /etc/default/motd-news

/etc/default/motd-news has
```
# Configure the source of dynamic MOTD news
# White space separated list of 0 to many news services
# For security reasons, these must be https
# and have a valid certificate
# Canonical runs a service at motd.ubuntu.com, and you
# can easily run one too
URLS="https://motd.ubuntu.com"

```