avoid automatic setting for contact email field

[daniele-andreotti]

We think that would be better to revert the PR #52 since when a issue is created and the user has not a valid email set, the email validation led to the following error:

Traceback (innermost last):
Module ZPublisher.WSGIPublisher, line 156, in transaction_pubevents
Module ZPublisher.WSGIPublisher, line 338, in publish_module
Module ZPublisher.WSGIPublisher, line 256, in publish
Module ZPublisher.mapply, line 85, in mapply
Module ZPublisher.WSGIPublisher, line 62, in call_object
Module plone.z3cform.layout, line 63, in call
Module plone.z3cform.layout, line 47, in update
Module plone.dexterity.browser.add, line 141, in update
Module plone.z3cform.fieldsets.extensible, line 65, in update
Module plone.z3cform.patch, line 30, in GroupForm_update
Module z3c.form.group, line 132, in update
Module z3c.form.form, line 136, in updateWidgets
Module z3c.form.field, line 277, in update
Module z3c.form.browser.text, line 36, in update
Module z3c.form.browser.widget, line 171, in update
Module Products.CMFPlone.patches.z3c_form, line 47, in _wrapped
Module z3c.form.widget, line 115, in update
Module zope.schema._bootstrapfields, line 112, in get
Module zope.schema._bootstrapfields, line 291, in validate
Module plone.schema.email, line 33, in _validate
plone.schema.email.InvalidEmail

[mauritsvanrees]

But we do really need an email address. We want to be able to send a mail to the user when there is an update.

This only leads to a validation error, right? Or does Plone show a '500 Internal Server Error'?