fmt: remove unused field from printer struct

Change-Id: I0ec775c51f461c6f0cbff88e796a7af55b736fcb
Reviewed-on: https://go-review.googlesource.com/20838Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/fmt/print.go

@@ -103,7 +103,6 @@ func (bp *buffer) WriteRune(r rune) {
 }
 
 type pp struct {
-	n         int
 	panicking bool
 	erroring  bool // printing an error condition
 	buf       buffer