关闭save_series FLAG后coredump

[lhsoft]

Describe the bug
关闭save_series,启动直接core dump

To Reproduce

Expected behavior

Versions
OS:
Compiler:
brpc:
protobuf:

Additional context/screenshots

在 LatencyRecorder::expose中有一个CHECK_EQ

CHECK_EQ(0, _latency_percentiles.set_vector_names(namebuf));

但在关闭save_series时，PassiveStatus::set_vector_names返回-1，导致core

 int set_vector_names(const std::string& names) {
          if (_series_sampler) {
              _series_sampler->set_vector_names(names);
              return 0;
          }
          return -1;
     }