BUG/MINOR: http: Fix bug introduced in previous patch in http_resync_states

The previous patch ("MINOR: http: Rely on analyzers mask to end processing in
forward_body functions") contains a bug for keep-alive transactions.

For these transactions, AN_REQ_FLT_END and AN_RES_FLT_END analyzers must be
removed only when all outgoing data was forwarded.
diff --git a/src/proto_http.c b/src/proto_http.c
index e5212cc..f9dc8a1 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -5665,9 +5665,11 @@
 			s->req.flags |= CF_WAKE_WRITE;
 		else if (s->res.buf->o)
 			s->res.flags |= CF_WAKE_WRITE;
-		s->req.analysers = AN_REQ_FLT_END;
-		s->res.analysers = AN_RES_FLT_END;
-		txn->flags |= TX_WAIT_CLEANUP;
+		else {
+			s->req.analysers = AN_REQ_FLT_END;
+			s->res.analysers = AN_RES_FLT_END;
+			txn->flags |= TX_WAIT_CLEANUP;
+		}
 	}
 }