Couple of minor fixes

Hello

Here is a couple a minor fixes.

Please pay attention to commit d56fc78 where I change macro $HOSTALIAS$ to $HOSTNAME$. Shinken doesn't enforce the presence of the alias directive in hosts config, and it's default value seems to be the name of the template used for service definition. I changed to $HOSTNAME$ to make the notifications more meaningful and for consistency with the host notification command.