BUG/MINOR: stream: Fix test on SE_FL_ERROR on the wrong entity

There is a bug at begining of process_stream(). The SE_FL_ERROR flag is
tested against backend stream-connector's flags instead of its SE
descriptor's flags. It is an old typo, introduced when the stream-interfaces
were replaced by the conn-streams.

This patch must be backported as far as 2.6.
diff --git a/src/stream.c b/src/stream.c
index 803dbe8..cbcdfef 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -1782,7 +1782,7 @@
 		if (!((scf->flags | scb->flags) & (SC_FL_SHUTR|SC_FL_SHUTW)) &&
 		    !((req->flags | res->flags) & (CF_READ_EVENT|CF_READ_TIMEOUT|CF_WRITE_EVENT|CF_WRITE_TIMEOUT)) &&
 		    !(s->flags & SF_CONN_EXP) &&
-		    !((sc_ep_get(scf) | scb->flags) & SE_FL_ERROR) &&
+		    !((sc_ep_get(scf) | sc_ep_get(scb)) & SE_FL_ERROR) &&
 		    ((s->pending_events & TASK_WOKEN_ANY) == TASK_WOKEN_TIMER)) {
 			scf->flags &= ~SC_FL_DONT_WAKE;
 			scb->flags &= ~SC_FL_DONT_WAKE;