Fix broken Travis CI build about drupal-container HOT 1 CLOSED

$ attempts=0
max_attempts=60
echo "Waiting for Drupal to complete setup."
until $(curl --output /dev/null --silent --head --fail http://localhost:8080/); do
    if [ ${attempts} -eq ${max_attempts} ];then
      echo "Timeout while waiting for Drupal to complete setup."
      exit 1
    fi
    printf '.'
    attempts=$(($attempts+1))
    sleep 5
done
Waiting for Drupal to complete setup.
curl: (56) Recv failure: Connection reset by peer
.curl: (22) The requested URL returned error: 500 500 Service unavailable (with message)
.curl: (22) The requested URL returned error: 500 500 Service unavailable (with message)
.curl: (22) The requested URL returned error: 500 500 Service unavailable (with message)