misc/git: add gofmt git pre-commit hook
misc/git: add gofmt git pre-commit hook

R=golang-dev, bradfitz, ftrvxmtrx, franciscossouza, r, minux.ma
CC=golang-dev
http://codereview.appspot.com/6843044

tv42/old-go,pombredanne/go-deleteme,dsriram/golang,apparentlymart/golang,dsriram/golang,tv42/old-go,pombredanne/go-deleteme,apparentlymart/golang,dsriram/golang,dsriram/golang,tv42/old-go,tv42/old-go,dsriram/golang,apparentlymart/golang,gnanderson/go,tv42/old-go,apparentlymart/golang,pombredanne/go-deleteme,pombredanne/go-deleteme,pombredanne/go-deleteme,gnanderson/go,gnanderson/go,tv42/old-go,apparentlymart/golang,gnanderson/go,gnanderson/go,pombredanne/go-deleteme,pombredanne/go-deleteme,dsriram/golang,gnanderson/go,gnanderson/go,dsriram/golang,apparentlymart/golang,apparentlymart/golang,tv42/old-go