migrate/functional: always run tests on CoreOS image

migrate/functional/README.md

@@ -7,7 +7,7 @@ This functional test suite deploys a etcd cluster using processes, and asserts e
 Dependencies
 ------------
 
-The test suite can only be run in linux system. It's recommended to run this in a virtual machine environment on CoreOS (e.g. using coreos-vagrant). The only dependency for the tests not provided on the CoreOS image is go.
+The test suite can only be run in CoreOS system. It's recommended to run this in a virtual machine environment on CoreOS (e.g. using coreos-vagrant). The only dependency for the tests not provided on the CoreOS image is go.
 
 Usage
 -----

migrate/functional/member.go

@@ -54,7 +54,6 @@ func NewProcWithDefaultFlags(path string) *Proc {
 	}
 	// always expect to use start_desired_verson mode
 	p.Env = append(p.Env,
-		"ETCD_ALLOW_LEGACY_MODE=true",
 		"ETCD_BINARY_DIR="+binDir,
 	)
 	return p