Fix leaked plugin files for syslog server
Fix leaked plugin files for syslog server

This PR fixes a leaking of the unix socket used when launching a syslog
server for the Docker driver.

Fixes https://github.com/hashicorp/nomad/issues/2844

frundh/nomad,Ashald/nomad,kmalec/nomad,dvusboy/nomad,dvusboy/nomad,kmalec/nomad,burdandrei/nomad,Ashald/nomad,nak3/nomad,kmalec/nomad,hashicorp/nomad,Ashald/nomad,nak3/nomad,dvusboy/nomad,hashicorp/nomad,burdandrei/nomad,nak3/nomad,burdandrei/nomad,frundh/nomad,nak3/nomad,kmalec/nomad,burdandrei/nomad,hashicorp/nomad,frundh/nomad,Ashald/nomad,frundh/nomad,kmalec/nomad,dvusboy/nomad,nak3/nomad,frundh/nomad,frundh/nomad,Ashald/nomad,dvusboy/nomad,dvusboy/nomad,kmalec/nomad,hashicorp/nomad,dvusboy/nomad,burdandrei/nomad,frundh/nomad,hashicorp/nomad,kmalec/nomad,burdandrei/nomad,nak3/nomad,nak3/nomad,burdandrei/nomad,Ashald/nomad,hashicorp/nomad,Ashald/nomad