compare-ligand-structures action: assign filename as structure name

restores old behaviour but as far as I can see, this change has no
consequence at all.

actions/ost-compare-ligand-structures

@@ -530,6 +530,9 @@ def _LoadStructureData(receptor_path,
     else:
         raise RuntimeError("This should never happen")
 
+    # assign filename as name to receptor
+    receptor.SetName(receptor_path)
+
     return (receptor, ligands)