Merge ~troyanov/maas:ipmi-power-off-mode-settings into maas:master

[Anton Troyanov]

fix: add power-off-mode to ipmi settings

Existing behaviour was:

```
if power_off_mode == "soft":
  ipmipower_command.append("--soft")
else:
  ipmipower_command.append("--off")
```

This basically mimics the same approach that was exposed via API, where for the method `def power_off(self, request, system_id)` we had "hard" to be the default value:

```
stop_mode = request.POST.get("stop_mode", "hard")
```

And also the Node model has defaults as "hard":
`def stop(self, user=None, stop_mode="hard", comment=None)`

The name for the exposed property is "power-off-mode" as thats how existing IPMI driver wants it (not the "stop_mode")
```
power_info.power_parameters["power_off_mode"] = stop_mode
```

[Alberto Donato (ack)]

+1

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b ipmi-power-off-mode-settings lp:~troyanov/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 7a0f6d02c4ed71ed5a558c9536b8de3a15bcf309

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b ipmi-power-off-mode-settings lp:~troyanov/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 30c7dc590e3d3c369fce2135e3963b8b7fe04a10

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b ipmi-power-off-mode-settings lp:~troyanov/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: aba365a591d3c79fdd2bb18a2d5e81f8fc8836ae

review: Approve

[Adam Collard (adam-collard)]

review: Approve

[Peter Makowski (petermakowski)]

review: Approve

diff --git a/src/provisioningserver/drivers/power/ipmi.py b/src/provisioningserver/drivers/power/ipmi.py
index f3f0806..752ae66 100644
--- a/src/provisioningserver/drivers/power/ipmi.py
+++ b/src/provisioningserver/drivers/power/ipmi.py
@@ -233,6 +233,11 @@ IPMI_WORKAROUND_FLAG_CHOICES = [
     ["", "None"],
 ]
 
+IPMI_POWER_OFF_MODE_CHOICES = [
+    ["soft", "Soft power off"],
+    ["hard", "Power off"],
+]
+
 
 @enum.unique
 class IPMI_PRIVILEGE_LEVEL(enum.Enum):
@@ -306,6 +311,14 @@ class IPMIPowerDriver(PowerDriver):
         make_setting_field(
             "mac_address", "Power MAC", scope=SETTING_SCOPE.NODE
         ),
+        make_setting_field(
+            "power_off_mode",
+            "Power off mode",
+            field_type="choice",
+            choices=IPMI_POWER_OFF_MODE_CHOICES,
+            default="hard",
+            required=False,
+        ),
     ]
     ip_extractor = make_ip_extractor("power_address")
     wait_time = (4, 8, 16, 32)
diff --git a/src/provisioningserver/tests/test_power_driver_command.py b/src/provisioningserver/tests/test_power_driver_command.py
index 93aaace..3ea8a5a 100644
--- a/src/provisioningserver/tests/test_power_driver_command.py
+++ b/src/provisioningserver/tests/test_power_driver_command.py
@@ -111,6 +111,8 @@ class TestPowerDriverCommand(MAASTestCase):
                 "opensesspriv",
                 "--workaround-flags",
                 "authcap",
+                "--power-off-mode",
+                "hard",
             ]
         )