Update config.sample.php
Update config.sample.php

clarify documentation. Fixes https://github.com/owncloud/core/issues/2624 
endsguy/server,cernbox/core,nextcloud/server,IljaN/core,pollopolea/core,andreas-p/nextcloud-server,whitekiba/server,endsguy/server,bluelml/core,sharidas/core,michaelletzgus/nextcloud-server,jbicha/server,xx621998xx/server,endsguy/server,Ardinis/server,owncloud/core,bluelml/core,endsguy/server,andreas-p/nextcloud-server,pollopolea/core,pmattern/server,owncloud/core,michaelletzgus/nextcloud-server,jbicha/server,cernbox/core,bluelml/core,xx621998xx/server,pmattern/server,sharidas/core,bluelml/core,pollopolea/core,phil-davis/core,bluelml/core,lrytz/core,pixelipo/server,endsguy/server,whitekiba/server,IljaN/core,lrytz/core,pollopolea/core,IljaN/core,Ardinis/server,pixelipo/server,michaelletzgus/nextcloud-server,owncloud/core,Ardinis/server,cernbox/core,owncloud/core,cernbox/core,pixelipo/server,lrytz/core,whitekiba/server,sharidas/core,jbicha/server,pmattern/server,xx621998xx/server,nextcloud/server,pmattern/server,nextcloud/server,sharidas/core,owncloud/core,cernbox/core,Ardinis/server,andreas-p/nextcloud-server,whitekiba/server,andreas-p/nextcloud-server,sharidas/core,andreas-p/nextcloud-server,whitekiba/server,xx621998xx/server,jbicha/server,pixelipo/server,lrytz/core,nextcloud/server,IljaN/core,jbicha/server,Ardinis/server,IljaN/core,pollopolea/core,michaelletzgus/nextcloud-server,pixelipo/server,lrytz/core,pmattern/server,xx621998xx/server