Save As - return copied datastore object

When a datastore object is copied, return the new object to the caller.

src/sugar3/datastore/datastore.py

@@ -470,6 +470,9 @@ def copy(ds_object, mount_point):
     ds_object -- DSObject to copy
     mount_point -- mount point of the new datastore entry
 
+    Returns:
+    new_ds_object -- DSObject copied
+
     """
     new_ds_object = ds_object.copy()
     new_ds_object.metadata['mountpoint'] = mount_point
@@ -490,6 +493,8 @@ def copy(ds_object, mount_point):
 
     write(new_ds_object)
 
+    return new_ds_object
+
 
 def get_unique_values(key):
     """Retrieve an array of unique values for a field.