Redhat: handle /etc/sysconfig/network better

Redhat: handle /etc/sysconfig/network better

The NETWORKING and NETWORKING_IPV6 variables are now setup
in setup_network instead of set_hostname, which now only
sets the hostname.

This changes the variable order so the testcase had to be
adapted.

Note that the HOSTNAME update s// now uses \h instead of \s
for horizontal spaces so it doesn't eat up newlines at the
end of file (caught by the testcase).