Add py37 and remove py35 in envlst

1. Update tox.ini file, add py37 and remove py35 in envlst for UT.
2. Upgrade pylint,astroid,keystoneauth1  version

Change-Id: Ibb7a5ad85343d0ffe5c50d6c72865bce6657ea36

lower-constraints.txt

@@ -1,5 +1,5 @@
 alabaster==0.7.10
-astroid==1.3.8
+astroid==1.6.5
 Babel==2.5.3
 certifi==2018.1.18
 chardet==3.0.4
@@ -20,7 +20,7 @@ idna==2.6
 imagesize==1.0.0
 iso8601==0.1.12
 Jinja2==2.10
-keystoneauth1==3.16.0
+keystoneauth1==3.18.0
 linecache2==1.0.0
 logilab-common==1.4.1
 MarkupSafe==1.0
@@ -36,7 +36,7 @@ pep8==1.5.7
 prettytable==0.7.2
 pyflakes==0.8.1
 Pygments==2.2.0
-pylint==1.4.5
+pylint==1.9.2
 pyparsing==2.2.0
 pyperclip==1.6.0
 python-freezerclient==2.0.0

test-requirements.txt

@@ -7,10 +7,15 @@ hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
 coverage!=4.4,>=4.0 # Apache-2.0
 mock>=2.0.0 # BSD
 oslo.config>=5.2.0 # Apache-2.0
-pylint==1.4.5 # GPLv2
+#pylint==1.4.5 # GPLv2
 testrepository>=0.0.18 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT
 unittest2>=1.1.0 # BSD
 sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7'  # BSD
 sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4'  # BSD
 oslosphinx>=4.7.0 # Apache-2.0
+astroid==1.6.5;python_version<"3.0" # LGPLv2.1
+astroid==2.1.0;python_version>="3.0" # LGPLv2.1
+pylint==1.9.2;python_version<"3.0" # GPLv2
+pylint==2.3.1;python_version>="3.0" # GPLv2
+

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py27,pep8,py35,py36,py3-{dj111,dj22},pylint
+envlist = py27,py36,py37,py3-{dj111,dj22},pep8,pylint,docs
 minversion = 2.0
 skipsdist = True
 
@@ -19,6 +19,15 @@ commands =
    dj22: pip install django>=2.2,<2.3
    python manage.py test {posargs}
 
+[testenv:py27]
+basepython = python2.7
+
+[testenv:py36]
+basepython = python3.6
+
+[testenv:py37]
+basepython = python3.7
+
 [testenv:pep8]
 basepython = python3
 commands = flake8 {posargs}