bst-artifact-server: Fix error handling for requests forwarded to casd
Without explicit error forwarding, the gRPC runtime wraps the error of a forwarded request with status UNKNOWN
"Exception calling application". The proxying should be transparent, though. The bst-artifact-server client should get the underlying error without any wrapping.
This branch also sets the _bytestream
stub variable to None
in CASDChannel.close()
, matching the other gRPC stubs.