Cleanup tox.ini

Remove old and unused constraint environments.

Note: Constraints were unused in CI before and stay unused since
cursive is not part of global requirements process.

Change-Id: I29b8eda7d99b815893da0cadc2341053bee436be

tox.ini

@@ -1,42 +1,25 @@
 [tox]
 minversion = 2.0
-envlist = py34-constraints,py27-constraints,pep8-constraints
+envlist = py34,py27,pep8
 skipsdist = True
 
 [testenv]
 usedevelop = True
-install_command =
-                  constraints: {[testenv:common-constraints]install_command}
-                  pip install -U {opts} {packages}
+install_command = pip install -U {opts} {packages}
 setenv =
    VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/test-requirements.txt
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
-[testenv:common-constraints]
-install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
-
 [testenv:pep8]
 commands = flake8 {posargs}
 
-[testenv:pep8-constraints]
-install_command = {[testenv:common-constraints]install_command}
-commands = flake8 {posargs}
-
 [testenv:venv]
 commands = {posargs}
 
-[testenv:venv-constraints]
-install_command = {[testenv:common-constraints]install_command}
-commands = {posargs}
-
 [testenv:cover]
 commands = python setup.py test --coverage --testr-args='{posargs}'
 
-[testenv:cover-constraints]
-install_command = {[testenv:common-constraints]install_command}
-commands = python setup.py test --coverage --testr-args='{posargs}'
-
 [testenv:docs]
 commands = python setup.py build_sphinx
 
@@ -44,17 +27,9 @@ commands = python setup.py build_sphinx
 commands =
   sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
-[testenv:docs-constraints]
-install_command = {[testenv:common-constraints]install_command}
-commands = python setup.py build_sphinx
-
 [testenv:debug]
 commands = oslo_debug_helper {posargs}
 
-[testenv:debug-constraints]
-install_command = {[testenv:common-constraints]install_command}
-commands = oslo_debug_helper {posargs}
-
 [flake8]
 # E123, E125 skipped as they are invalid PEP-8.