Update doctor.js
Update doctor.js

use watson-developer-cloud instead of watson-developer-cloud-alpha
jthomas/doctor-watson,IBM-Bluemix/doctor-watson,jthomas/doctor-watson,IBM-Bluemix/doctor-watson,cemoulto/doctor-watson,kannanagasamy/doc-watson-kannan,kannanagasamy/doc-watson-kannan,erikasf/doctor-watson,erikasf/doctor-watson,cemoulto/doctor-watson