os: change return variable name for Getwd to avoid confusion changed (pwd string) to (dir string), as some think pwd means passwd. Fixes issue 7811.
os: change return variable name for Getwd to avoid confusion
changed (pwd string) to (dir string), as some think pwd means passwd.
Fixes issue 7811.

LGTM=iant
R=golang-codereviews, iant, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/89100043

apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang