Fix duplicate lines in policy.json

Removed duplicate lines from etc/nova/policy.json file.

Commit [1] introduced the delete targets with empty rules
and commit [2] changed them in Liberty incompletely to
admin_or_owner rules.

[1] 9c91781604
[2] 09a55e2bf4

Change-Id: I9081ccf28ec72a2d791cddac0597efef67e56429
Closes-Bug:1577370

etc/nova/policy.json

@@ -85,9 +85,6 @@
     "compute:security_groups:add_to_instance": "",
     "compute:security_groups:remove_from_instance": "",
 
-    "compute:delete": "",
-    "compute:soft_delete": "",
-    "compute:force_delete": "",
     "compute:restore": "",
 
     "compute:volume_snapshot_create": "",

nova/tests/unit/test_policy.py

@@ -368,6 +368,9 @@ class RealRolePolicyTestCase(test.NoDBTestCase):
 "default",
 "compute:start",
 "compute:stop",
+"compute:delete",
+"compute:soft_delete",
+"compute:force_delete",
 "compute_extension:admin_actions:pause",
 "compute_extension:admin_actions:unpause",
 "compute_extension:admin_actions:suspend",
@@ -405,8 +408,6 @@ class RealRolePolicyTestCase(test.NoDBTestCase):
 "compute:create",
 "compute:create:attach_network",
 "compute:create:attach_volume",
-"compute:delete",
-"compute:force_delete",
 "compute:get_all_instance_metadata",
 "compute:get_all_instance_system_metadata",
 "compute:get_console_output",
@@ -452,7 +453,6 @@ class RealRolePolicyTestCase(test.NoDBTestCase):
 "compute:security_groups:remove_from_instance",
 "compute:set_admin_password",
 "compute:snapshot",
-"compute:soft_delete",
 "compute:suspend",
 "compute:swap_volume",
 "compute:unlock",