Incorrect process detection ("Process is already running")

[drewmnoel]

Description

The new process detection (in 420558e) seems to be problematic when run with sudo. This is probably because sudo creates another copy of the process entry with root permissions, and then runs that. So there will be two copies in the process list.

If I switch to root, the command works just fine.

How to reproduce

1. Run sudo docker-gc

What do you expect

Command completes successfully

What happened instead

docker-gc detects the original sudo request as a separate process, and refuses to run

Software:

• bash version: GNU bash, version 4.3.42(1)-release
• fgrep version: grep (GNU grep) 2.25
• sudo version: Sudo version 1.8.16

Full backtrace

$ sudo docker-gc
[Mon Jun 27 11:47:26 EDT 2016] : docker-gc : Process is already running with PID 6817

[mattnworb]

hey @drewmnoel thanks for the heads up. I've reverted that previous change at #112