backout r1426: return dynamic weights

src/http/ngx_http_upstream_round_robin.c

diff --git a/src/http/ngx_http_upstream_round_robin.c b/src/http/ngx_http_upstream_round_robin.c
index 441a1aa..106d645 100644
--- a/src/http/ngx_http_upstream_round_robin.c
+++ b/src/http/ngx_http_upstream_round_robin.c
@@ -515,7 +515,7 @@
 
         for (i = 0; i < peers->number; i++) {
             if (peer[i].fails == 0) {
-                peer[i].current_weight = peer[i].weight;
+                peer[i].current_weight += peer[i].weight;
 
             } else {
                 /* 1 allows to go to quick recovery when all peers failed */