make dbus available to mailsync service

This may be needed if imap/smtp passwords are stored in gnome-keyring or
somesuch.

roles/mail/tasks/mailsync.yml

@@ -5,7 +5,7 @@
     - mailsync
 
 - name: Push mailsync service file
-  copy: src=mailsync.service dest=/etc/systemd/system/mailsync@.service
+  template: src=mailsync.service.j2 dest=/etc/systemd/system/mailsync@.service
   tags:
     - mailsync
   notify:

roles/mail/templates/mailsync.service.j2

@@ -8,3 +8,4 @@ ExecStart=/usr/local/bin/mailsync
 User=%i
 StandardOutput=syslog
 StandardError=syslog
+Environment=DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/{{ user.uid }}/bus