cabal: fix Data-files syntax

36b1d769 removed the last entry from
this list but did not remove the trailing comma from the previous line.

When I am king, all file formats will support trailing commas in lists.

bustle.cabal

@@ -13,7 +13,7 @@ Homepage:       https://gitlab.freedesktop.org/bustle/bustle#readme
 Data-files:     data/bustle.ui,
                 data/FilterDialog.ui,
                 data/OpenTwoDialog.ui,
-                data/RecordAddressDialog.ui,
+                data/RecordAddressDialog.ui
 Build-type:     Custom
 Extra-source-files:
                   -- C bits