This also incorporates the version string into the package name so
that incompatibile versions will fail to connect.
Arbitrary choices:
- The proto3 package name is runtime.v1alpha2. The proto compiler
normally translates this to a go package of "runtime_v1alpha2", but
I renamed it to "v1alpha2" for consistency with existing packages.
- kubelet/apis/cri is used as "internalapi". I left it alone and put the
public "runtimeapi" in kubelet/apis/cri/runtime.
Whenever pod sandbox needs to be recreated, all containers associated
with it will be killed by kubelet. This change ensures that the init
containers will be rerun in such cases.
The change also refactors the compute logic so that the control flow of
init containers act is more aligned with the regular containers. Unit
tests are added to verify the logic.
