Remove stale pip-missing-reqs tox test
pip_missing_reqs tool is no longer maintained and has broken with release 10 of pip
Refer to:
@@ -162,14 +162,6 @@ max-complexity=30
local-check-factory = cinder.hacking.checks.factory
import_exceptions = cinder.i18n
-[testenv:pip-missing-reqs]
-# do not install test-requirements as that will pollute the virtualenv for
-# determining missing packages
-# this also means that pip-missing-reqs must be installed separately, outside
-# of the requirements.txt files
-deps = pip_check_reqs>=2.0.1
-commands = pip-missing-reqs -d --ignore-file=cinder/tests/* cinder
-
[testenv:lower-constraints]
basepython = python3
deps =
