Don't SIGINT ourselves on bad daemon data

Summary:
If daemon data is mangled, bin/phd restart will SIGINT process 0, which kills it.

uh oh T.T so sad

Test Plan: Used bin/phd start to start daemons; removed PID information from one; saw bin/phd stop shut down cleanly and not kill itself.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: mholden, epriestley

Differential Revision: https://secure.phabricator.com/D10308