cashew: libcurl http fetcher: use default CA certificate path

src/service.cc

Index: src/service.cc
diff --git a/src/service.cc b/src/service.cc
index 1bb11055dd5b92644738b391f557c36be84032b7..210609c72d9e72aefedd539c62d641ad775ef5bc 100644
--- a/src/service.cc
+++ b/src/service.cc
@@ -432,9 +432,9 @@ void Service::OnUsageUrlUpdate(const std::string& usage_url) {
   }
   usage_url_ = usage_url;
   if (provider_ != NULL) {
-    DCHECK(usage_url != provider_->GetUsageUrl());
+    DCHECK(usage_url_ != provider_->GetUsageUrl());
     StopSendingUsageRequests();
-    provider_->SetUsageUrl(usage_url);
+    provider_->SetUsageUrl(usage_url_);
     ReconsiderSendingUsageRequests();
   }
 }