Add controller prefix to disk location column

This fixes rhev tests that were broken when the infra manager parser it
inherits from was changed to include the controller prefix to the disk location.

See: ManageIQ/manageiq-providers-ovirt#662

spec/models/manageiq/providers/redhat/infra_manager/refresher/refresher_4_async_graph_spec.rb

@@ -513,7 +513,7 @@ def assert_specific_vm_powered_on
         :controller_type => "virtio",
         :present         => true,
         :filename        => "08b054b2-0001-4dd6-9cf2-434213c02fbe",
-        :location        => "0",
+        :location        => "0:0",
         :size            => 8_589_934_592,
         :size_on_disk    => 2_561_437_696,
         :mode            => "persistent",
@@ -656,7 +656,7 @@ def assert_specific_vm_powered_off
         :controller_type => "virtio",
         :present         => true,
         :filename        => "738dc6a9-c7ff-4bd4-8f37-d0e4fdc0ff76",
-        :location        => "0",
+        :location        => "0:0",
         :size            => 46_137_344,
         :size_on_disk    => 204_800,
         :mode            => "persistent",
@@ -766,7 +766,7 @@ def assert_specific_template
         :controller_type => "virtio",
         :present         => true,
         :filename        => "2d41b00f-d594-47dd-9148-931731ddf8ff",
-        :location        => "0",
+        :location        => "0:0",
         :size            => 46_137_344,
         :size_on_disk    => 12_775_424,
         :mode            => "persistent",