The first start of a Consul Connect proxy sidecar triggers a run
of the envoy_version hook which modifies the task config image
entry. The modification takes into account a number of factors to
correctly populate this. Importantly, once the hook has run, it
marks itself as done so the taskrunner will not execute it again.
When the client receives a non-destructive update for the
allocation which the proxy sidecar is a member of, it will update
and overwrite the task definition within the taskerunner. In doing
so it overwrite the modification performed by the hook. If the
allocation is restarted, the envoy_version hook will be skipped as
it previously marked itself as done, and therefore the sidecar
config image is incorrect and causes a driver error.
The fix removes the hook in marking itself as done to the view of
the taskrunner.
