drush make does not fail or throw an error when attempting to unzip an archive when unzip is not installed

This issue also exists in the version of drush_make for 4.5 and would be an easy backport.

I discovered this issue when working with Vagrant; the make was working perfectly - except for libraries that came from ZIP files. Turns out unzip wasn't installed in the base box.

To replicate on Ubuntu 8.04 without unzip installed:

drush make --no-core test.make test
jquery.ui downloaded from http://jquery-ui.googlecode.com/files/jquery-ui-1.7.3.zip. [ok]
ls -la test/sites/all/libraries/jquery.ui

Result: 4.5 - empty directory
Result: 5.1 - jquery-ui-1.7.3.zip

This is tangentially related to http://drupal.org/node/1457798 - Use drush_tarball_extract() and drush filesystem commands during make. The fix I'm proposing doesn't cover that, it just throws an error if unzip fails for whatever reason.