aws-ebs-csi-driver: remove preStop hook

The hook can cause issue on execution, like

```
Exec lifecycle hook ([/bin/sh -c rm -rf
/registration/ebs.csi.aws.com-reg.sock /csi/csi.sock]) for Container
"node-driver-registrar" in Pod
"ebs-csi-node-96jbk_ebs-csi(a82c6d41-bd2b-42dd-b092-e3acd4c43b62)"
failed - error: command '/bin/sh -c rm -rf
/registration/ebs.csi.aws.com-reg.sock /csi/csi.sock' exited with 126: ,
message: "OCI runtime exec failed: exec failed: container_linux.go:370:
starting container process caused: exec: \"/bin/sh\": stat /bin/sh: no
such file or directory: unknown\r\n"
```

Moreover, it has been deleted from upstream driver, see this patch
6e59160eea

Signed-off-by: Nicolas Sterchele <foss@sterchelen.net>

upup/models/cloudup/resources/addons/aws-ebs-csi-driver.addons.k8s.io/k8s-1.17.yaml.template

@@ -337,10 +337,6 @@ spec:
             - --csi-address=$(ADDRESS)
             - --kubelet-registration-path=$(DRIVER_REG_SOCK_PATH)
             - --v=5
-          lifecycle:
-            preStop:
-              exec:
-                command: ["/bin/sh", "-c", "rm -rf /registration/ebs.csi.aws.com-reg.sock /csi/csi.sock"]
           env:
             - name: ADDRESS
               value: /csi/csi.sock