Refactor apps load_certs/load_crls to work incrementally

Reviewed-by: Richard Levitte <levitte@openssl.org>

apps/s_client.c

diff --git a/apps/s_client.c b/apps/s_client.c
index 4dea7c4..717d7c1 100644
--- a/apps/s_client.c
+++ b/apps/s_client.c
@@ -1331,9 +1331,8 @@
     }
 
     if (chain_file) {
-        chain = load_certs(chain_file, FORMAT_PEM,
-                           NULL, e, "client certificate chain");
-        if (!chain)
+        if (!load_certs(chain_file, &chain, FORMAT_PEM, NULL, e,
+                        "client certificate chain"))
             goto end;
     }