[tox] Drop jenkins stuff

tox.ini

@@ -24,17 +24,6 @@ deps =
   flake8
 commands = flake8 {posargs:{toxinidir}}
 
-[testenv:flake8-jenkins]
-skip_install = true
-whitelist_externals =
-  flake8
-deps =
-  flake8 > 2.3.0
-  flake8-junit-report
-commands =
-  flake8 {toxinidir} --output-file=flake8.txt
-  flake8_junit flake8.txt test-results.xml
-
 [flake8]
 max-line-length = 100
 exclude = cubicweb_skos/migration,.tox