ssmtp: Drop important flag from info.xml

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
squid: Add missing info.xml

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
nagios: Push all the files needed for NagiosGen

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>