Fix gcl to pass in the suggested owners properly in order to fix the bug introduced in r78329 (we were passing in a generator to the owners object and it needed to be a list). Fix a couple of other minor bugs related to suggesting reviewers while we're at it.

R=chase@chromium.org,maruel@chromium.org
Review URL: http://codereview.chromium.org/6673104

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@78486 0039d316-1c4b-4281-b951-d872f2087c98