Shorten ceph s3-tests tox environment names
Shorten ceph s3-tests tox environment names

Apparently long names cause issues when the job is running in the gate?

Change-Id: I4b9def2ce867580fb0f5b6b64818eef6d65b7a43
Related-Change: I80a7a32a415c27ac9de9d72591ed293ac8546cba

stackforge/swift3,swiftstack/swift3-stackforge,stackforge/swift3,swiftstack/swift3-stackforge