encoding/ianaindex: fix issue in gen.go

Not sure how this happened.

TBR

Change-Id: If8ae5f93d3848e128cc0353a9aedad4c6e3694a7
Reviewed-on: https://go-review.googlesource.com/38367
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
1 file changed