Correct some of the manual tasks details for Ubuntu 16.04

[douglascrp]

Hey @loftux

I noticed that when you install Alfresco in a 16.04 server, the correct file to be configured in the manual tasks is /opt/alfresco/alfresco-service.sh, not /etc/init/alfresco.conf as stated here https://github.com/loftuxab/alfresco-ubuntu-install/blob/master/alfinstall.sh#L878

Also, there is a problem in this line https://github.com/loftuxab/alfresco-ubuntu-install/blob/master/alfinstall.sh#L894
sudo service alfresco start should be sudo /opt/alfresco/alfresco-service.sh start or sudo systemctl start alfresco.service

I know everything is explained at the project's page correctly, but I think it would be nice to show the right info just after the install process is finished.

One more small thing. Into the libreoffice.sh section, include a line break in the crontab lines.
Not important if you know what you are doing, but for those not that well informed, it can be a problem.