Check for SS_NBIO in so->so_state instead of sb->sb_flags in
soreceive_stream().

Differential Revision:	https://reviews.freebsd.org/D1299
Reviewed by:	bz, gnn
MFC after:	1 week


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275808 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f