Change VirtualMedia interface after design update.

Latest changes in VirtualMedia design
(https://github.com/openbmc/docs/commit/9de2f4eea01d7daa6ccff3c7615e6954a36900fc,
https://github.com/openbmc/docs/commit/a3d687046c223a2b9d8c575f3f26a59733d6794b)
adds signal field to Proxy and Legacy interfaces.

Tested:
Compiles, signature consistent with implementation

Change-Id: If6f00607f4e46cf95f2bdbfa8a5c854c43f077f1
Signed-off-by: Przemyslaw Czarnowski <przemyslaw.hawrylewicz.czarnowski@intel.com>
diff --git a/yaml/xyz/openbmc_project/VirtualMedia/Legacy.interface.yaml b/yaml/xyz/openbmc_project/VirtualMedia/Legacy.interface.yaml
index b55f65a..611c426 100644
--- a/yaml/xyz/openbmc_project/VirtualMedia/Legacy.interface.yaml
+++ b/yaml/xyz/openbmc_project/VirtualMedia/Legacy.interface.yaml
@@ -1,10 +1,10 @@
 description: >
-    This interface provides methods for mounting and unmounting images
+   This interface provides methods for mounting and unmounting images
     using the legacy mode.
 
 methods:
     - name: Mount
-      description: Perform a mount to HOST operation on given object.
+      description: Perform an asynchronous operation of mounting to HOST on given object.
       parameters:
           - name: ImageURL
             type: string
@@ -28,10 +28,21 @@
           - xyz.openbmc_project.Common.Error.InternalFailure
 
     - name: Unmount
-      description: Perform an unmount from HOST on given object.
+      description: Perform an asynchronous operation of unmounting from HOST on given object.
       returns:
           - name: Status
             type: boolean
             description: the unmount status. True on success.
       errors:
           - xyz.openbmc_project.Common.Error.InternalFailure
+
+signals:
+    - name: Completion
+      description: >
+        Signal indicating completion of mount or unmount action.
+      properties:
+        - name: Result
+          type: int32
+          description: >
+            Returns 0 for success or errno on failure after background
+            operation completes.
diff --git a/yaml/xyz/openbmc_project/VirtualMedia/Proxy.interface.yaml b/yaml/xyz/openbmc_project/VirtualMedia/Proxy.interface.yaml
index 8299c72..6b08c69 100644
--- a/yaml/xyz/openbmc_project/VirtualMedia/Proxy.interface.yaml
+++ b/yaml/xyz/openbmc_project/VirtualMedia/Proxy.interface.yaml
@@ -3,7 +3,8 @@
 
 methods:
     - name: Mount
-      description: Perform a mount to HOST operation on given object.
+      description: >
+        Perform an asynchronous operation of mounting to HOST on given object.
       returns:
           - name: Status
             type: boolean
@@ -12,10 +13,23 @@
           - xyz.openbmc_project.Common.Error.InternalFailure
 
     - name: Unmount
-      description: Perform an unmount from HOST on given object.
+      description: >
+        Perform an asynchronous operation of unmount from HOST on given
+        object.
       returns:
           - name: Status
             type: boolean
             description: the unmount status. True on success.
       errors:
           - xyz.openbmc_project.Common.Error.InternalFailure
+
+signals:
+    - name: Completion
+      description: >
+        Signal indicating completion of mount or unmount action.
+      properties:
+        - name: Result
+          type: int32
+          description: >
+            Returns 0 for success or errno on failure after background
+            operation completes.