* OpenEXRConfig.h.in uses version extracted from openexr_version.h

The logic was already in place to extract the version from
`openexr_version.h`, so the `.in` file just needed to reference the
proper CMake variables. This also duplicates the `OpenEXR_VERSION_*`
settings to `OPENEXR_VERSION_*`.

Signed-off-by: Cary Phillips <cary@ilm.com>

* bazel

Signed-off-by: Cary Phillips <cary@ilm.com>

* comment

Signed-off-by: Cary Phillips <cary@ilm.com>

* fix formatting of core version test error message

Signed-off-by: Cary Phillips <cary@ilm.com>

* fix extra comparison test

Signed-off-by: Cary Phillips <cary@ilm.com>

---------

Signed-off-by: Cary Phillips <cary@ilm.com>