Update build.lock for moved nrpe-external-master interface
The original repository for the npre-external-master repository was
removed and was re-uploaded [1]. This changed the commit hash for the
build.lock. This patch updates the commit hash to point to the head of
the new repository main branch as it hasn't changed since 2017.
* use stable/21.10 libraries
* use zaza/zaza-openstack-tests at stable/21.10
* build.lock files for reactive charms
* bundles refer to ~openstack-charms candidate channel
* update tox/pip.sh to ensure setuptools<50.0.0
When running TestManilaCharm.test_install() with py36 sometimes
test passes and sometimes throws and error while mocking methods.
Seems to be an async race problem mocking a super method first.
This was solved by avoiding mocking super method first.
