Revision 1716352

Following up on r1716346, fix hpack decoding to work like the other decode buckets
and don't return eof from the processing when the bucket is not done yet. Remove
unneeded callback as callers just want to read the headers.

* buckets/hpack_buckets.c
  (serf_hpack_decode_ctx_t): Remove callback.
  (serf__bucket_hpack_decode_create): Remove two arguments.
  (handle_read_entry_and_clear): Remove callback handling.
  (hpack_process): Return success on EOF.

* protocols/fcgi_protocol.c
  (fcgi_process): Handle empty read.

* protocols/http2_buckets.h
  (serf__bucket_hpack_decode_create): Remove arguments. Tweak comment.

* protocols/http2_protocol.c
  (http2_process): Handle empty read.
  (http2_process): Update caller.

* protocols/http2_stream.c
  (stream_promise_item): Remove function.
  (serf_http2__stream_handle_hpack): Update caller.