Rename `version` to `ociVersion` according to runtime.md
Rename `version` to `ociVersion` according to runtime.md

According to definition of [state](runtime.md#State), we should rename
`version` field in `state.go` to `ociVersion`

Signed-off-by: Zhang Wei <14976e959b2860fb06a3c1edbdb1945a4e11b8b5@huawei.com>

wking/opencontainer-runtime-spec,opencontainers/runtime-spec,hqhq/runtime-spec,wking/opencontainer-specs,cloudfoundry-incubator/specs,opencontainers/specs,laijs/specs,hqhq/specs