Fix int casting of lastBytePos in DefaultStorageRpc.read

[mziccard]

This depends on googleapis/google-api-java-client#937. MediaHttpDownloader.setContentRange takes firstBytePos as a long while lastBytePos as an int. As soon as this gets fixed we need to remove int casting.

[aozarov]

While googleapis/google-api-java-client#937 was not fixed yet we no longer use the MediaHttpDownloader and therefore this is not an issue for us anymore.

[Venkata96]

@aozarov What do we use instead of MediaHttpDownloader? How do we download a chunk

[aozarov]

see the associate change or current code.