Revert "Use a bitmask to represent role attributes"

This reverts commit 1826987a46.

The overall design was deemed unacceptable, in discussion following the
previous commit message; we might find some parts of it still
salvageable, but I don't want to be on the hook for fixing it, so let's
wait until we have a new patch.

src/backend/catalog/Catalog.pm

@@ -176,7 +176,7 @@ sub Catalogs
 				}
 			}
 		}
-		$catalogs{$catname} = \%catalog if defined $catname;
+		$catalogs{$catname} = \%catalog;
 		close INPUT_FILE;
 	}
 	return \%catalogs;