Don't use `unzip -t` when `unzip -l` will do.

It's a *lot* more expensive, and ziptool doesn't support it. I can
easily add the functionality, but since our only user seems to be a
mistake, that wouldn't be my first choice!

Test: treehugger
Change-Id: Iab1a326e4cec3520942adaf9f3c9bb424adf4c35
1 file changed