misc/vim: send Fmt errors to the quickfix list instead of the location list.
misc/vim: send Fmt errors to the quickfix list instead of the location list.

Output from gofmt is a list of errors, so they should appear in the error list.

R=adg
CC=golang-dev
https://codereview.appspot.com/33760043

pombredanne/go-deleteme,tv42/old-go,pombredanne/go-deleteme,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,tv42/old-go