It is the error registry that should register the display, not
the error handler. Move this function to the class that is
responsible for it.

Change-Id: I95ca1662b907a7f38a42a39ec729b35fd530bb79
Reviewed-on: https://gerrit.libreoffice.org/36853Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Chris Sherlock <chris.sherlock79@gmail.com>