tput: No value for $TERM and no -T specified

Since we got `set -e` at [line11](https://github.com/hyperhq/hyper-installer/blob/master/hyper-bootstrap.sh#L11)

``` bash
9 |  BASE_DIR=$(cd "$(dirname "$0")"; pwd); cd ${BASE_DIR}
10|  SLEEP_SEC=10
11|  set -e
12|  ########## Variable ##########
13|  CURRENT_USER="$(id -un 2>/dev/null || true)"
```

Running this script under no $TERM global environment variable would cause non-zero exit.
