Remove launchd overrides

This code hasn't been used for years. Its original intention was to
allow a service to define, in its plist, `inetdCompatibility = Wait`,
then let launchd start it on demand. No services currently use this,
and the overrides plist is *gone* on OS X 10.10.

Fixes #104
Merge pull request #111 from boxen/yosemite

Remove launchd overrides