TS-1006: adjust some reclaimable-freelist's default configuration

1) Adjust "enable_reclaim" to "1" as default in
   records.config.default.in file.

2) Adjust "max_overage" to "3" in code, so that it keeps the same value
   with records.config.default.in. And most important, this value seems
   work well in our product environment.

Signed-off-by: Yunkai Zhang <qiushu.zyk@taobao.com>
TS-2090 Make proxy.config.allocator.enable_reclaim default based on build instructions