cdap.sh is very brittle and needs some refactoring

The problem is in the way we start the process and then grep the logs for a message that says "Reactor started successfully". That was recently changed to "Application Server started successfully". Hence reactor comes up but the script never recognizes that and keeps waiting.

I fixed that by allowing arbitrary text before the "started successfully". This works because currently no other messages of that form appear in the cdap.log (they may be in cdap-debug.log).