aegea launch should not die if SFR instance is terminated during waiting period

[kislyuk]

INFO:aegea:Launching <aegea.util.aws.SpotFleetBuilder object at 0x10f6c9908: {'cores': 1, 'dry_run': False, 'gpus_per_instance': 0, 'iam_fleet_role': iam.Role...otFleet'), ...}>
Traceback (most recent call last):
  File "/Users/kislyuk/projects/mutt/build/mutt-master/VE/bin/aegea", line 23, in <module>
    aegea.main()
  File "/Users/kislyuk/projects/mutt/build/mutt-master/VE/lib/python2.7/site-packages/aegea/__init__.py", line 58, in main
    result = parsed_args.entry_point(parsed_args)
  File "/Users/kislyuk/projects/mutt/build/mutt-master/VE/lib/python2.7/site-packages/aegea/launch.py", line 142, in launch
    instance.wait_until_running()
  File "/Users/kislyuk/projects/mutt/build/mutt-master/VE/lib/python2.7/site-packages/boto3/resources/factory.py", line 369, in do_waiter
    waiter(self, *args, **kwargs)
  File "/Users/kislyuk/projects/mutt/build/mutt-master/VE/lib/python2.7/site-packages/boto3/resources/action.py", line 202, in __call__
    response = waiter.wait(**params)
  File "/Users/kislyuk/projects/mutt/build/mutt-master/VE/lib/python2.7/site-packages/botocore/waiter.py", line 53, in wait
    Waiter.wait(self, **kwargs)
  File "/Users/kislyuk/projects/mutt/build/mutt-master/VE/lib/python2.7/site-packages/botocore/waiter.py", line 321, in wait
    last_response=response,
botocore.exceptions.WaiterError: Waiter InstanceRunning failed: Waiter encountered a terminal failure state