kubectlbuildwrapper: simplify, set context in common path

src/main/java/org/csanchez/jenkins/plugins/kubernetes/KubectlBuildWrapper.java

@@ -93,6 +93,9 @@ public void setUp(Context context, Run<?, ?> build, FilePath workspace, Launcher
         FilePath configFile = workspace.createTempFile(".kube", "config");
         Set<String> tempFiles = newHashSet(configFile.getRemote());
 
+        context.env("KUBECONFIG", configFile.getRemote());
+        context.setDisposer(new CleanupDisposer(tempFiles));
+
         String tlsConfig;
         if (caCertificate != null && !caCertificate.isEmpty()) {
             FilePath caCrtFile = workspace.createTempFile("cert-auth", "crt");
@@ -130,9 +133,6 @@ public void setUp(Context context, Run<?, ?> build, FilePath workspace, Launcher
             } finally {
                 reader.close();
             }
-
-            context.setDisposer(new CleanupDisposer(tempFiles));
-            context.env("KUBECONFIG", configFile.getRemote());
             return;
         }
 
@@ -191,10 +191,6 @@ public void setUp(Context context, Run<?, ?> build, FilePath workspace, Launcher
                 .cmdAsSingleString("kubectl config --kubeconfig=\"" + configFile.getRemote() + "\" use-context k8s")
                 .join();
         if (status != 0) throw new IOException("Failed to run kubectl config "+status);
-
-        context.setDisposer(new CleanupDisposer(tempFiles));
-
-        context.env("KUBECONFIG", configFile.getRemote());
     }
 
     /**