live: use .ant image as main image after image creation error

Restore image file from .ant to original file name if new image
creation fails. Remove new imagen and move the .ant image file in
place of the original as previously an error meant a rename of the
image file without a revert to keep the image available.

src/live/ogOperations.py

@@ -504,6 +504,12 @@ class OgLiveOperations:
 
             image_info = ogGetImageInfo(image_path)
         except Exception as e:
+            if os.path.exists(image_path):
+                os.unlink(image_path)
+
+            if os.path.exists(f'{image_path}.ant'):
+                shutil.move(f'{image_path}.ant', image_path)
+
             self._restartBrowser(self._url)
             raise RuntimeError(f'Failed to create image for {fstype} filesystem in device {padev}: {e}') from e