slipstream.bootstrap should make sure that executor started successfully

[konstan]

https://github.com/slipstream/SlipStreamClient/blob/master/client/src/main/scripts/slipstream.bootstrap.py#L845

Instead it should make sure that in case of the executor daemon it was successfully started and in case if not - set the corresponding abort flag.

There might be dependency issues on the VM in which case executor daemon simply not able to start and on UI there is no way to know what has happened.