live: clean files after a failed cache image copy

Remove image files after a failed image copy operation.

src/live/ogOperations.py

@@ -208,6 +208,13 @@ class OgLiveOperations:
             r = shutil.copy(src, dst)
             tip_write_csum(image_name)
         except (OSError, OgError) as e:
+            try:
+                if os.path.exists(dst):
+                    os.unlink(dst)
+                if os.path.exists(f"{dst}.full.sum"):
+                    os.unlink(f"{dst}.full.sum")
+            except OSError as e:
+                pass
             raise OgError(f'Error copying image {image_name} to cache. Reported: {e}') from e
 
         if (not os.path.exists(dst)):