Statsd proxy ignores SIGTERM signal

When StatsD is run as a cluster proxy it will ignore the SIGTERM signal.

Steps to reproduce:

• create a proxy config from the default example cp exampleProxyConfig.js proxyConfig.js
• run the proxy using your config node proxy.js proxyConfig.js
• try terminating the parent process kill <node pid>

Expected result: statsd proxy terminates

Actual result: statsd proxy keeps running

Could be because process_mgmt.init is never invoked from proxy.js I have only tested from within a docker container, but should be reproducible in other environments as well.