I tried this locally and it seems to work. Going to self-merge, can't make things worse than they are right now.

GCE e2e build/test passed for commit 6e6ae45.

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With a second look at the code, having unique prefix in etcd does not help at all. Most integration tests use framework.DeleteAllEtcdKeys(), which remove everything from etcd. I tried to look for a way how to pass the unique prefix to it, but integration tests are started in so many different ways that I gave up:

• RunAMaster
• NewMasterComponents
• NewMasterConfig (used directly by service account tests)
• NewIntegrationTestMasterConfig (again, used directly by many tests)