build and version info on admin page. trial #2

I changed the subprocess calls from:
`subprocess.check_output(["git rev-parse --abbrev-ref HEAD"])`
to:
`subprocess.check_output(["git", "rev-parse", "--abbrev-ref", "HEAD"])`

Though I'm not sure if that was the problem. Does running the following in the terminal work?
`git rev-parse --abbrev-ref HEAD`