tox: Update astroid/pylint to 1.4.1/1.5.0.

This means logilab-common isn't needed anymore and it runs with python 3.5 now.

tox.ini

@@ -97,7 +97,6 @@ commands =
     {envpython} scripts/dev/run_vulture.py
 
 [testenv:pylint]
-basepython = python3.4
 ignore_errors = true
 skip_install = true
 setenv = PYTHONPATH={toxinidir}/scripts/dev
@@ -105,9 +104,8 @@ passenv =
 deps =
     {[testenv]deps}
     {[testenv:misc]deps}
-    astroid==1.3.8
-    pylint==1.4.4
-    logilab-common==1.1.0
+    astroid==1.4.1
+    pylint==1.5.0
     requests==2.8.1
 commands =
     {envpython} scripts/link_pyqt.py --tox {envdir}