Stop traversing hidden (dot) directories when searching for Dart files

Stop traversing hidden (dot) directories when searching for Dart files. I don't know that this is the only place that needs to be changed, but I know it's one place.
Committed: https://code.google.com/p/dart/source/detail?r=7621

[pquitslund, 2012-05-14 19:24:47]

LGTM.

(Aside: the whitespace churn surprises me a little since I thought we had
standardized and applied new settings....  Anyway, I'll assume we're converging
on something standard and won't worry about it unless we see this keep
happening.  Net-net: no biggie!)

[Brian Wilkerson, 2012-05-14 19:35:22]

> (Aside: the whitespace churn surprises me a little since I thought we had
> standardized and applied new settings...

Sorry about that. We did, and I don't know why that happened. (I didn't even
notice it until you pointed it out.) I'll keep an eye out for future churn.

[pquitslund, 2012-05-14 19:36:39]

On 2012/05/14 19:35:22, Brian Wilkerson wrote:
> > (Aside: the whitespace churn surprises me a little since I thought we had
> > standardized and applied new settings...
> 
> Sorry about that. We did, and I don't know why that happened. (I didn't even
> notice it until you pointed it out.) I'll keep an eye out for future churn.

No prob.  Thanks!