Upstream: restored workaround for "if".

The 7022564a9e0e changeset made ineffective workaround from 2464ccebdb52
to avoid NULL pointer dereference with "if".  It is now restored by
moving the u->ssl_name initialization after the check.

Found by Coverity (CID 1210408).
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index a645383..de3ff13 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -584,9 +584,6 @@
     if (u->resolved == NULL) {
 
         uscf = u->conf->upstream;
-#if (NGX_HTTP_SSL)
-        u->ssl_name = uscf->host;
-#endif
 
     } else {
 
@@ -680,6 +677,10 @@
         return;
     }
 
+#if (NGX_HTTP_SSL)
+    u->ssl_name = uscf->host;
+#endif
+
     if (uscf->peer.init(r, uscf) != NGX_OK) {
         ngx_http_upstream_finalize_request(r, u,
                                            NGX_HTTP_INTERNAL_SERVER_ERROR);