Remove ZUUL_PATCHSET

Removing old ZUUL_ env variables which have been replaced with
Ansible variables.

Change-Id: Iac4be1734af7d501dc87c281d5668e7f8d211a66
diff --git a/tests/unit/test_github_driver.py b/tests/unit/test_github_driver.py
index ec90cd6..a28abb1 100644
--- a/tests/unit/test_github_driver.py
+++ b/tests/unit/test_github_driver.py
@@ -37,7 +37,7 @@
         build_params = self.builds[0].parameters
         self.assertEqual('master', build_params['ZUUL_BRANCH'])
         self.assertEqual(str(A.number), build_params['ZUUL_CHANGE'])
-        self.assertEqual(A.head_sha, build_params['ZUUL_PATCHSET'])
+        self.assertEqual(A.head_sha, build_params['zuul']['patchset'])
 
         self.executor_server.hold_jobs_in_build = False
         self.executor_server.release()
diff --git a/zuul/executor/client.py b/zuul/executor/client.py
index e5a7eb1..26036a7 100644
--- a/zuul/executor/client.py
+++ b/zuul/executor/client.py
@@ -209,7 +209,6 @@
                                      for i in all_items])
             params['ZUUL_CHANGE_IDS'] = zuul_changes
             params['ZUUL_CHANGE'] = str(item.change.number)
-            params['ZUUL_PATCHSET'] = str(item.change.patchset)
 
         params['job'] = job.name
         params['timeout'] = job.timeout