[hab] Fail on artifact upload if an unknown error is encountered.
[hab] Fail on artifact upload if an unknown error is encountered.

This was a source of where the client was blindly ignoring an issue that
the Depot service wasn't properly communicating back. Instead of being
optimistic here, we're going to be terribly pessimistic and die at the
source of the failure.

rsertelon/habitat,georgemarshall/habitat,georgemarshall/habitat,habitat-sh/habitat,nathenharvey/habitat,rsertelon/habitat,rsertelon/habitat,nathenharvey/habitat,georgemarshall/habitat,rsertelon/habitat,nathenharvey/habitat,georgemarshall/habitat,nathenharvey/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,georgemarshall/habitat,rsertelon/habitat,habitat-sh/habitat,georgemarshall/habitat,habitat-sh/habitat,georgemarshall/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat,nathenharvey/habitat,nathenharvey/habitat,georgemarshall/habitat,habitat-sh/habitat