app: debug state initialization fix
app: debug state initialization fix

* Fixes issue with Flask not setting app.debug until after the
  application creation, causing e.g. template auto-reloading or
  Flask-DebugToolbar to not be correctly initialized.

Signed-off-by: Lars Holm Nielsen <7eaffca9f7cd98839b5821d0d23e09ff764b82cd@cern.ch>

inveniosoftware/invenio-base,tiborsimko/invenio-base,inveniosoftware/invenio-base,tiborsimko/invenio-base