Change contributor normalization for jboss.org jira content in DCP not to use email but username

Change contributor normalization for jboss.org jira content in DCP not to use email but jboss.org username as jira do not return emails over REST API in case of some jira configuration (email visibility in general configuration).
This will work well as we replicate contributor information to the DCP from Jive so jboss.org username is available there.