Remove lower-constraints remnants

These were missed in change I2706e8af350d07e51169f8bc13c7404d4696b2a2

Change-Id: Ie6e15bdc948dcc918fd2eff344f804ac93434f1b
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

lower-constraints.txt

@@ -1,34 +0,0 @@
-appdirs==1.3.0
-argparse==0.9.0
-cliff==3.1.0
-cmd2==0.8.9
-coverage==4.0
-dulwich==0.15.0
-extras==1.0.0
-fixtures==3.0.0
-future==0.18.2
-iso8601==0.1.11
-keystoneauth1==3.4.0
-linecache2==1.0.0
-os-client-config==1.28.0
-oslotest==3.2.0
-pbr==2.0.0
-prettytable==0.7.2
-pyparsing==2.4.7
-pyperclip==1.8.0
-python-mimeparse==1.6.0
-python-subunit==1.0.0
-reno==3.1.0
-requests==2.14.2
-requestsexceptions==1.2.0
-six==1.10.0
-stestr==2.0.0
-stevedore==1.20.0
-testrepository==0.0.20
-testtools==2.2.0
-toml==0.9.3
-traceback2==1.4.0
-unittest2==1.1.0
-virtualenv==20.0.8
-voluptuous==0.11.7
-wcwidth==0.2.4

tox.ini

@@ -28,11 +28,12 @@ deps =
   -r{toxinidir}/doc/requirements.txt
 commands =
   doc8 --ignore-path "doc/source/history.rst" doc/source
-  sphinx-build -W -b html doc/source doc/build/html
+  sphinx-build -a -E -W -b html doc/source doc/build/html
 
 [testenv:releasenotes]
 deps = {[testenv:docs]deps}
-commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
+commands =
+  sphinx-build -a -E -W -b html releasenotes/source releasenotes/build/html
 
 [testenv:bindep]
 # Do not install any requirements. We want this to be fast and work even if
@@ -45,12 +46,6 @@ deps = bindep
 commands = bindep test
 usedevelop = False
 
-[testenv:lower-constraints]
-deps =
-  -c{toxinidir}/lower-constraints.txt
-  -r{toxinidir}/test-requirements.txt
-  -r{toxinidir}/requirements.txt
-
 [flake8]
 show-source = True
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build