fix: universe extensions in gapfill

In commit cd57c56, only carve.py was adapted to read the universe files from the .xml.gz files, not the .xml files (which were deleted in the same commit). gapfill then was failing as standalone command, as it could not find the universe files.

carveme/cli/gapfill.py

@@ -33,7 +33,7 @@ def maincall(inputfile, media, mediadb=None, universe=None, universe_file=None,
 
     if not universe_file:
         if universe:
-            universe_file = "{}{}universe_{}.xml".format(project_dir, config.get('generated', 'folder'), universe)
+            universe_file = "{}{}universe_{}.xml.gz".format(project_dir, config.get('generated', 'folder'), universe)
         else:
             universe_file = project_dir + config.get('generated', 'default_universe')