refactor, get rid of `contact_info.get_email2`.

This method was called from exactly one place.
It handled 6 different kind of inputs but the only reference
called with with only 2 distinct inputs. Those inputs then
both share the same duck-type interface.

There is no need for indirection, which is not used.
Merge pull request #228 from 4teamwork/refactor_email2

refactor, get rid of `contact_info.get_email2`.