packaging: modified validation of fqdn input during setup

validateFQDN now explicitly states that an IP address is not
supported instead of just saying "<ip address here> did not resolve
to an ip address. User input failed validation..."

Change-Id: I99d3727f0e2205f6cd90ff5c2a003fb6f0643eab
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=843623
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>