Rename SwiftScenarioTest to ObjectStorageScenarioTest

This commit renames SwiftScenarioTest to ObjectStorageScenarioTest
because of the consistency. The name of the other scenario test classes
are service name not project name: e.g. Network, Baremetal, etc.

Change-Id: I701b9ba9fda536b50b2fcbf6922f0b64f6404bf7
3 files changed