Fix some malloc error handling.

Thanks to Tom Thorogood for catching this.

Change-Id: I09fa5d9822b9ba13b106add251e26c6ebee21b03
Reviewed-on: https://boringssl-review.googlesource.com/29825
Reviewed-by: Tom Thorogood <me+google@tomthorogood.co.uk>
Reviewed-by: Steven Valdez <svaldez@chromium.org>
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/ssl_lib.cc b/ssl/ssl_lib.cc
index 52f1ccd..9084610 100644
--- a/ssl/ssl_lib.cc
+++ b/ssl/ssl_lib.cc
@@ -2057,8 +2057,8 @@
   if (!PushToStack(ctx->cert_compression_algs.get(), std::move(alg))) {
     if (sk_CertCompressionAlg_num(ctx->cert_compression_algs.get()) == 0) {
       ctx->cert_compression_algs.reset();
-      return 0;
     }
+    return 0;
   }
 
   return 1;