MINOR: mux-quic: Set abort info for SC-less QCS on STOP_SENDING frame
It is a revert of
cc9827bb09 ("BUG/MEDIUM: mux-quic: fix crash on
STOP_SENDING received without SD"). This fix was based on a wrong assumption
about QUIC streams that may have no stream-endpoint descriptor. However, it
must never happen. And this was fixed. So we can now safely revert the
commit above. However, it is not a bugfix because, for now, abort info are
only used by the upper layer. So it is not a big deal to not set it when
there is no SC.