remove all traces of pylint testing infrastructure

The pylint tests have been broken for several months and
the Jenkins job has also been disabled. There has been
no sign of attempts to address this, so just delete what
remains of the pylint support so developers don't mistakenly
think it is supposed to work with patches they are submitting.

Change-Id: Ifacc99e45acb0e9a72be6c31113e0cf073354f02

.gitignore

@@ -39,5 +39,3 @@ nosetests.xml
 nova/tests/cover/*
 nova/vcsversion.py
 tools/conf/nova.conf*
-tools/lintstack.head.py
-tools/pylint_exceptions

test-requirements.txt

@@ -13,7 +13,6 @@ mox>=0.5.3
 mox3>=0.7.0
 MySQL-python
 psycopg2
-pylint>=1.3.0  # GNU GPL v2
 python-ironicclient>=0.2.1
 python-subunit>=0.0.18
 requests-mock>=0.5.1  # Apache-2.0

tox.ini

@@ -45,9 +45,6 @@ commands =
 commands =
   bash tools/config/generate_sample.sh -b . -p nova -o etc/nova
 
-[testenv:pylint]
-commands = bash tools/lintstack.sh
-
 [testenv:cover]
 # Also do not run test_coverage_ext tests while gathering coverage as those
 # tests conflict with coverage.