Make stop_timers() method public

This is needed to fix Heat bug 1315044.

Change-Id: I0f92235beaa1bfd548688c9b0803f9931bc9dac8
Remove requirements_style_check.sh

Per mordred, requirements should be listed in the order they
need to be installed, since pip doesn't "fix" anything listed
in the wrong order.

See also https://review.openstack.org/#/c/92221/

Change-Id: I467a3e597ffca24de01ed3d6bcbc26bd1501353b
Merge "Make stop_timers() method public"