Installing aliases for virtual robots automatically

Binary package hint: sympa

When creating a list for the default robot, the alias_manager automatically creates the new aliases, but for virtual robots, also a file with the virtual aliases is needed. This patch does that.

In addition, it removes the need to have write access to all alias-db-files (by using "/usr/sbin/postalias /etc/mail/sympa.aliases") instead of the aliaswrapper). Maybe using "/usr/bin/newaliases -oA/etc/mail/sympa.aliases" would be better for sendmail-compatibility).

The patch for alias_manager.pl is attached. Also included is the virtuals-template list_virtual.tt2 which should be put in /usr/share/sympa (alongside list_aliases.tt2)