transmute k8s init macOS-cluster fails when service account already exists

[Orie Steele]

##### create tiller service account
Error from server (AlreadyExists): serviceaccounts "tiller" already exists
exec: 
real	0m1.957s
user	0m0.561s
sys	0m0.211s
Error from server (AlreadyExists): serviceaccounts "tiller" already exists

/usr/local/lib/node_modules/transmute-cli/src/commands/runner.js:8
    throw new Error('Command FAILED, tell us what happened so we can fix it: https://github.com/transmute-industries/transmute/issues/new');

[Orie Steele]

if [ -e "kubectl get serviceaccounts tiller -n kube-system" ]; then
    echo 'yes'
else
    echo 'no'
fi