Merge "Allow drm hal implementations to not require provisioning"

     * certificate authority (CA) is an entity which issues digital certificates

     * for use by other parties. It is an example of a trusted third party.

     * @return status the status of the call. The status must be OK or one of

     * the following errors: BAD_VALUE if the sessionId is invalid or

     * ERROR_DRM_INVALID_STATE if the HAL is in a state where the provision

     * the following errors: BAD_VALUE if the sessionId is invalid,

     * ERROR_DRM_CANNOT_HANDLE if the drm scheme does not require provisioning

     * or ERROR_DRM_INVALID_STATE if the HAL is in a state where the provision

     * request cannot be generated.

     * @return request if successful the opaque certificate request blob

     * is returned