t3306 failure with v1.7.5-rc1

[Michael J Gruber <git@drmicha.warpmail.net>]

Heya,

I get this stupid test failure in test 3 of t3306. The problem is that a
dangling commit does not get pruned away when it should:

3rd
test_must_fail: command succeeded: git cat-file -p
5ee1c35e83ea47cd3cc4f8cbee0568915fbbbd29
not ok - 4 verify that commits are gone

It's a system where make complains about funny clock (I dunno why) but
can we make this more robust? The following helps with "sleep 5" but not
with "sleep 4". test_tick does not help. What's going on?

---

diff --git i/t/t3306-notes-prune.sh w/t/t3306-notes-prune.sh
index c428217..da76463 100755
--- i/t/t3306-notes-prune.sh
+++ w/t/t3306-notes-prune.sh
@@ -62,7 +62,9 @@ test_expect_success 'remove some commits' '

 	git reset --hard HEAD~1 &&
 	git reflog expire --expire=now HEAD &&
+	sleep 5 &&
 	git gc --prune=now
 '

 test_expect_success 'verify that commits are gone' '