collect: add filter for Blueprints

* Upgrades to Flask-Collect>=1.1.1

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
What do you think about keeping this file and adding https://docs.python.org/2/library/exceptions.html#exceptions.DeprecationWarning or https://docs.python.org/2/library/exceptions.html#exceptions.ImportWarning