README: update openSUSE instructions
The `zypper ar` line resulted in an error as a repo name is required.
Given the `-f` (autorefresh) option is specified, manually refreshing (`zypper ref`) is not really needed.
@@ -164,8 +164,8 @@ alternative option below.
#### openSUSE ####
- # zypper ar -f obs://server:http
- # zypper ref && zypper in goaccess
+ # zypper ar -f obs://server:http http
+ # zypper in goaccess
#### OpenIndiana ####
