Delete the lb configuration files during cleanup

The issue is seen because boost::filesystem::remove
is used to delete the lb pool configuration directory.
Since the directory is not empty, it is failing.

This patch fixes the issue by calling
boost::filesystem::remove_all instead of delete
the files if the directory is not empty.

Change-Id: I0b22c985aacee9173f1537f029fdc51c6db0324b
Closes-bug: #1399241

src/vnsw/agent/oper/namespace_manager.cc

@@ -696,7 +696,7 @@ void NamespaceManager::LoadbalancerObserver(
             haproxy_->GenerateConfig(pathgen.str(), loadbalancer->uuid(),
                                      *loadbalancer->properties());
         } else {
-             boost::filesystem::remove(pathgen.str(), error);
+             boost::filesystem::remove_all(pathgen.str(), error);
              if (error) {
                  LOG(ERROR, error.message());
                  return;