Revert "BUG/MINOR: server: Remove FQDN requirement for using init-addr and state...

Revert "BUG/MINOR: server: Remove FQDN requirement for using init-addr and state file"

This reverts commit 19e8aa58f7c42e602a95b4ceb4b254c424aed11c.

It causes some trouble reported by Manu :
   listen tls
     [...]
     server bla 127.0.0.1:8080

   [ALERT] 248/130258 (21960) : parsing [/etc/haproxy/test.cfg:53] : 'server bla' : no method found to resolve address '(null)'
   [ALERT] 248/130258 (21960) : Failed to initialize server(s) addr.

According to Nenad :
  "It's not a good way to fix the issue we were experiencing
   before. It will need a bigger rewrite, because the logic in
   srv_iterate_initaddr needs to be changed."