Bug#348478: exim4: /etc/mailname not included in local_domains

[Igor Belyi]

I do believe that besides update-exim4.conf.8 you also need to fix 
exim4-config.templates which caused
me to make the same mistake of not including mailname by saying:

Template: exim4/dc_other_hostnames
Type: string
Default:
Description: Other destinations for which mail is accepted:
 Please enter a list of domains for which this machine should consider
 itself the final destination, apart from the local hostname (${fqdn})
 and "localhost".

Cheers,
Igor