Fix comment

[TomH, 2012-07-09 19:06:05]

We actually do name the function GrProgramStageFactory::glStageKey().

The static function GenKey() exists on classes named GrGL*, so probably doesn't
need an extra GL in its name.

[TomH, 2012-07-09 19:06:45]

(Responding to comment in http://codereview.appspot.com/6379043/ that we should
fix naming of these functions.)

[bsalomon, 2012-07-09 19:07:12]

On 2012/07/09 19:06:45, TomH wrote:
> (Responding to comment in http://codereview.appspot.com/6379043/ that we
should
> fix naming of these functions.)

LGTM

[TomH, 2012-07-09 19:07:54]

Closed in r4489.