change etherpad process monitoring to check for server.js instead of safeRun.sh

check for:
node node_modules/ep_etherpad-lite/node/server.js

and exactly 1 process, not more or less

RT #5790

Change-Id: I439c967f8f62a707f172ac620e07df70ca4b9e6e
Merge "change etherpad process monitoring to check for server.js instead of safeRun.sh" into production