types: remove Init{Sha1,Path}
types: remove Init{Sha1,Path}

In preparation for removing dockerinit upstream, remove the docker info
fields that relate to dockerinit.

Signed-off-by: Aleksa Sarai <a8eb12d32d6ec07cdf737175ec7d4a0f1b4e1ee7@suse.com>

rhatdan/engine-api,mikedougherty/engine-api,jwhonce/engine-api,thaJeztah/engine-api,vdemeester/engine-api,docker/engine-api,msabansal/engine-api