Revert "Replace oslo.sphinx with oslosphinx"

This reverts commit c926216a9bd64d5cdd9731bd34e03613940d32e9.

Conflicts:
	test-requirements.txt
notify calling process we are ready to serve

Systemd notification should be sent in-process, otherwise systemd might
miss the subprocess sending notification.
See systemd bug https://bugzilla.redhat.com/show_bug.cgi?id=820448

Taken from keystone project commit
abc06716d027d68f0da3b0f559fa7c85a21804d5

Improvements from Keystone version:

    * add unset_environment parameter
    New parameter unset_environment was added to sd_notify
    http://www.freedesktop.org/software/systemd/man/sd_notify.html
    to ensure service readiness is sent only once.

    * add onready() method to simulate systemd environment
    For testing purposes and optional use with SysV initscripts.

    * unit test added

    * docstrings for notification methods

Patch includes deployment in openstack.common.service.
It does not have an effect when running the service outside
the systemd environment.

Implements: blueprint service-readiness
Change-Id: I80f325c9be9c171c2dc8d5526570bf64f0f87c78
Move notification point to a better place

Follow-up for I80f325c9be9c171c2dc8d5526570bf64f0f87c78
"notify calling process we are ready to serve"

Xavier Queralt found issue with sending readiness notification from inside
run_service: it returns premature OK in case of multiple service endpoints
in one systemd service like nova-api which by default provides osapi, ec2 and
metadata services.

Instead, send readiness notification before entering wait loop for each
Launcher type.

Change-Id: I69bf10f353f5fecaaf89e537c2d3c46b73e39d36
Implements: blueprint service-readiness