Cannot turn off verbose output

[mike-potter]

Just installed prestissimo and now when I use "composer install" I get a lot of extra verbose output that I didn't get before. I see a verbose option that has default:false. My CURLOPT_VERBOSE isn't set at all. Doing a "composer --quiet install" fixes it, but I'd like to see the normal composer output. Examples of extra verbose output I am seeing:

Initially, several messages like:

3/9: http://packagist.org/p/provider-2013$75554497196180bf3fd60c1a3d12aeed755a07556a4e03eed84e63cd28e1e8df.json

After it checks for dependencies but before downloading, lots like this (one per package basically):

150/159:    https://codeload.github.com/symfony/http-kernel/legacy.zip/0e39ed020c6a4bfb888974414fbfe2779637a487

Any idea on how to make prestissimo quiet without using the full --quiet option on composer itself?