Refs #225 - Don't crash when hitting issue #225.
Refs #225 - Don't crash when hitting issue #225.

This is not a fix, but sync will not stop working if two contacts
share the same name, email and interests.

artfulrobot/uk.co.vedaconsulting.mailchimp,artfulrobot/uk.co.vedaconsulting.mailchimp,veda-consulting/uk.co.vedaconsulting.mailchimp,krishgopi/uk.co.vedaconsulting.mailchimp,krishgopi/uk.co.vedaconsulting.mailchimp,veda-consulting/uk.co.vedaconsulting.mailchimp