When we construct context object using Context.from_environ()
tenant_name is not passed while project_name is passed.
This commit makes project_name and tenant_name handled more equally.
Needed-By: Ie48aa843ca8c852b1e93e760d2e3e8aaa38aed56
Change-Id: Ieec57d9ea8d95e55499a17e2c04da5e3e78a1557