remove pep8/py3pep8 from jenkins, we run them in travis already (#3764)

diff --git a/Jenkinsfile b/Jenkinsfile
index 8c3c55f..d953a48 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -66,7 +66,7 @@
     [
         label: 'docker',
         imageName: 'pyca/cryptography-runner-ubuntu-rolling',
-        toxenvs: ['py27', 'py35', 'pep8', 'py3pep8', 'randomorder'],
+        toxenvs: ['py27', 'py35', 'randomorder'],
     ],
     [
         label: 'docker',