Drop Django 1.11 support

Django 1.11 ends its extended support in April 2020 (which is before
Ussuri release), so horizon drops Django 1.11 support in Ussuri.

tox envs for non-primary Django versions are no longer needed in tox.ini
as testing environments for non-primary Django versions are setup in
the zuul jobs now.

horizon>=17.1.0 is required to use Django 2.2. requirements.txt and
lower-constraints.txt are updated accordingly. for more info. please
refer [1].
Depends-On: https://review.opendev.org/#/c/700733/
[1] https://etherpad.openstack.org/p/Enable_Django22_support_in_Horizon_Plugin

Change-Id: I68ab10b4ac0e09b7d850e7c8f855a7e95c22d141

lower-constraints.txt

@@ -19,7 +19,7 @@ django-appconf==1.0.2
 django-babel==0.6.2
 django-compressor==2.0
 django-pyscss==2.0.2
-Django==1.11
+Django==2.2
 docutils==0.14
 dogpile.cache==0.6.5
 dulwich==0.19.0
@@ -29,7 +29,7 @@ fixtures==3.0.0
 flake8==2.5.5
 futurist==1.6.0
 hacking==0.12.0
-horizon==14.0.0
+horizon==17.1.0
 idna==2.6
 imagesize==1.0.0
 iso8601==0.1.12
@@ -81,7 +81,7 @@ pyScss==1.3.4
 python-dateutil==2.7.0
 python-designateclient==2.7.0
 python-glanceclient==2.9.1
-python-keystoneclient==3.15.0
+python-keystoneclient==3.22.0
 python-mimeparse==1.6.0
 python-neutronclient==6.7.0
 python-novaclient==10.1.0

requirements.txt

@@ -6,4 +6,4 @@ pbr!=2.1.0,>=2.0.0 # Apache-2.0
 Babel!=2.4.0,>=2.3.4 # BSD
 python-designateclient>=2.7.0 # Apache-2.0
 
-horizon>=14.0.0.0b3 # Apache-2.0
+horizon>=17.1.0 # Apache-2.0

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 1.6
-envlist = py37,py3-{dj111,dj22},pep8
+envlist = py37,pep8
 skipsdist = True
 
 [testenv]
@@ -20,8 +20,6 @@ deps = -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/
        -r{toxinidir}/test-requirements.txt
 
 commands =
-  dj111: pip install django>=1.11,<2
-  dj22: pip install django>=2.2,<2.3
   find . -type f -name "*.pyc" -delete
   {toxinidir}/manage.py test designatedashboard --settings=designatedashboard.tests.settings
 passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY