MustKillCouchbaseService fails on CBS 6.6.2

TestNodeServiceDownRecovery and TestRecoveryAfterOneNsServerFailureBucketOneReplica both use the method MustKillCouchbaseService(), which executes the following in a pod:

mv /etc/service/couchbase-server /tmp/

... in CBS 6.6.2, this command fails;

exec_util.go:143: Command: mv /etc/service/couchbase-server /tmp/

exec_util.go:144: stdout:

exec_util.go:145: stderr:

util.go:1288: command terminated with exit code 1

These tests pass in 6.5.2.