bdiff: one more safe call of bdiff_freehunks(NULL)

mercurial/cext/bdiff.c

@@ -157,9 +157,7 b' cleanup:'
 	PyBuffer_Release(&bb);
 	free(al);
 	free(bl);
-	if (l.next) {
 		bdiff_freehunks(l.next);
-	}
 	return result;
 }