profilemodel: fix nullptr access

my previous patch [cm: replace BLANK() by default ctor]
causes a nullptr access in ProfileModelPrivate::slotAccountAdded()
There is a call to acc->contactMethod() that returns a nullptr.

I really tried to understand this call and its impact...
... no success!
Removing the line seems to have no effect during tests on Gnome client.

LRC is magic!

Change-Id: Icdd33989e5d90bfb93227d82354643269fe944ff
Reviewed-by: Olivier Soldano <olivier.soldano@savoirfairelinux.com>