Fix pylint issues appeared with version 3.2.2 of pylint

Change-Id: Iae943e2a3b26b8eed616509ec9a3a4cbc493aa6e
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/tox.ini b/tox.ini
index ee43058..607d0d3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -64,7 +64,7 @@
 deps =  {[testenv]deps}
         -r{toxinidir}/requirements-dev.txt
         -r{toxinidir}/requirements-test.txt
-        pylint
+        pylint==3.2.2
 commands =
         pylint -E osmclient/