iosdeploystep did call reportFinished on the future interface.
This is incorrect, the finished signal should be emitted instead
This lead to a reuse of the future  due to missing call to
buildStepFinishedAsync which lead to failing on the second run of
the deploy step.

Change-Id: I96b8874bc98c77453d5c0af96c818dff6e955167
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>