git/log: show first commit as file change

We checked if the file was changed from its parents.
If there were no parents, the answer was no, but it
should be yes.

sys/src/cmd/git/log.c

@@ -119,7 +119,7 @@ filtermatch(Object *o)
 		if(r)
 			return 1;
 	}
-	return 0;
+	return o->commit->nparent == 0;
 }