deb: manage dabba user for daemon permissions.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
init.d: start dabbad server with the dabba user.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
dabbad: write pid file to /var/run/dabba

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
dabbad: create socket file in /var/run/dabba.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
init.d: use pidfile in /var/run/dabba.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
init.d: by /etc/init.d dabbad must be daemonized.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>