Remove deprecated comment
Remove deprecated comment

The session key is currently stored in SESSIONKEY.txt, so it is no longer reset
every time the server starts.

cloudfoundry-community/etherpad-lite-cf,KonradMil/etherpad-lite,ether/etherpad-lite,tiblu/etherpad-lite,joequant/etherpad-lite,rschiang/etherpad-lite,ether/etherpad-lite,University-of-Potsdam-MM/etherpad-lite,lpagliari/etherpad-lite,ether/etherpad-lite,aptivate/etherpad-lite,tiblu/etherpad-lite,storytouch/etherpad-lite,University-of-Potsdam-MM/etherpad-lite,aptivate/etherpad-lite,lpagliari/etherpad-lite,storytouch/etherpad-lite,KonradMil/etherpad-lite,rschiang/etherpad-lite,rschiang/etherpad-lite,University-of-Potsdam-MM/etherpad-lite,cloudfoundry-community/etherpad-lite-cf,joequant/etherpad-lite,aptivate/etherpad-lite,rschiang/etherpad-lite,KonradMil/etherpad-lite,joequant/etherpad-lite,cloudfoundry-community/etherpad-lite-cf,tiblu/etherpad-lite,storytouch/etherpad-lite,lpagliari/etherpad-lite,cloudfoundry-community/etherpad-lite-cf,joequant/etherpad-lite,aptivate/etherpad-lite,KonradMil/etherpad-lite,University-of-Potsdam-MM/etherpad-lite,tiblu/etherpad-lite,lpagliari/etherpad-lite