misc/emacs: fix indent bug
misc/emacs: fix indent bug

Must use case-sensitive search to identify keywords.

Fixes issue 2287.

R=bradfitz
CC=golang-dev
http://codereview.appspot.com/5182043

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang