Reversed the is:reviewable logic.
Reversed the is:reviewable logic.

Default to list_all, with an option to filter to just is:reviewable.

Change-Id: Ib3903e2114f8f287b5d96a887e6ac807541acb4f

jeeloo/git-review,entropia1/git-review,meelapshah/git-review,meelapshah/git-review,ka2m/git-review,openstack-infra/git-review