mock_driver: fix fingreprint key (#20351)

The `mock_driver` is an internal task driver used mostly for testing and
simulating workloads. During the allocrunner v2 work (#4792) its name
changed from `mock_driver` to just `mock` and then back to
`mock_driver`, but the fingreprint key was kept as `driver.mock`.

This results in tasks configured with `driver = "mock"` to be scheduled
(because Nomad thinks the client has a task driver called `mock`), but
fail to actually run (because the Nomad client can't find a driver
called `mock` in its catalog).

Fingerprinting the right name prevents the job from being scheduled in
the first place.

Also removes mentions of the mock driver from documentation since its an
internal driver and not available in any production release.

client/driver_manager_test.go

@@ -174,10 +174,6 @@ func TestDriverManager_NodeAttributes_Run(t *testing.T) {
 			return false, fmt.Errorf("mock_driver driver is not marked as healthy: %+v", d)
 		}
 
-		if d.Attributes["driver.mock_driver"] != "" {
-			return false, fmt.Errorf("mock driver driver attributes contain duplicate health info: %#v", d.Attributes)
-		}
-
 		// check raw_exec
 		if node.Attributes["driver.raw_exec"] == "" {
 			return false, fmt.Errorf("raw_exec is not present in attributes: %#v", node.Attributes)

drivers/mock/driver.go

@@ -345,7 +345,7 @@ func (d *Driver) buildFingerprint() *drivers.Fingerprint {
 		desc = "disabled"
 	} else {
 		health = drivers.HealthStateHealthy
-		attrs["driver.mock"] = pstructs.NewBoolAttribute(true)
+		attrs["driver.mock_driver"] = pstructs.NewBoolAttribute(true)
 		desc = drivers.DriverHealthy
 	}
 

website/content/api-docs/events.mdx

@@ -166,7 +166,6 @@ http://127.0.0.1:4646/v1/event/stream
             "driver.docker.os_type": "linux",
             "driver.docker.runtimes": "runc",
             "driver.docker.version": "19.03.13",
-            "driver.mock": "true",
             "driver.mock_driver": "1",
             "driver.raw_exec": "1",
             "kernel.name": "linux",
@@ -362,15 +361,6 @@ http://127.0.0.1:4646/v1/event/stream
               "HealthDescription": "Driver must run as root",
               "UpdateTime": "2020-10-15T10:07:37.445601605-04:00"
             },
-            "mock_driver": {
-              "Attributes": {
-                "driver.mock": "true"
-              },
-              "Detected": true,
-              "Healthy": true,
-              "HealthDescription": "Healthy",
-              "UpdateTime": "2020-10-15T10:07:37.445193068-04:00"
-            },
             "qemu": {
               "Attributes": null,
               "Detected": false,

website/content/api-docs/nodes.mdx

@@ -203,7 +203,6 @@ $ curl \
     "driver.docker.runtimes": "runc",
     "driver.docker.version": "18.09.6",
     "driver.docker.volumes.enabled": "true",
-    "driver.mock": "true",
     "driver.mock_driver": "1",
     "driver.raw_exec": "1",
     "kernel.name": "linux",
@@ -257,15 +256,6 @@ $ curl \
       "Healthy": false,
       "UpdateTime": "2019-08-26T12:22:50.687274359+02:00"
     },
-    "mock_driver": {
-      "Attributes": {
-        "driver.mock": "true"
-      },
-      "Detected": true,
-      "HealthDescription": "Healthy",
-      "Healthy": true,
-      "UpdateTime": "2019-08-26T12:22:50.687978919+02:00"
-    },
     "qemu": {
       "Attributes": null,
       "Detected": false,