The /healthcheck URL, as provided by oslo.middleware, is very
useful for operators to setup haproxy and to do monitoring.
Such feature is already in many services like Keystone, Glance,
and others.
The same type of patch has been approved in Neutronm, Heat, and
Cinder. It's under discussion in Nova, where they want to check
more than just the wsgi app, though the pricinple to add it has
been accepted already.
Change-Id: I8f24431db0ec88385b4b916e181d6da3e598c764
3321092928