selftest: Remove reduction in time window in delaywrite test

selftest: Remove reduction in time window in delaywrite test

This causes flakey autobuilds from time to time.

The reduction in the time window to 30% was added in:

commit c2df97f57ce205935c37cd5a90cfeddb129cd92b
Author: Jeremy Allison <jra@samba.org>
Date:   Thu Nov 5 15:37:26 2009 -0800

    Fix up some of the timing constants for DELAYWRITE. Add some extra tests up test_delayed_write_update6
    to investigate what happens to a sticky write handle after a second handle close.
    Jeremy.

The original reduction to 75% was set in the new code

commit 0d0fddf8ae856efd7ffb07ba8fa32d2f55d3f9c0
Author: Jeremy Allison <jra@samba.org>
Date:   Fri Sep 5 14:24:36 2008 -0700

    Added tests that show that write time update is immediate
    when changing file size using SMBwrite of size zero,
    SET_END_OF_FILE, or SET_ALLOCATION_SIZE - no 2 second
    delay in these cases.
    Jeremy.
    (This used to be commit 3aa7523d7750fe30d1e6bb5a75ac42b681b9e493)

and in:

commit edb3a83a069d39e123f18de098cfaab6deb16729
Author: Stefan Metzmacher <metze@samba.org>
Date:   Tue Apr 8 10:25:51 2008 +0200

    BASE-DELAYWRITE: use timeval_* and make it possible to spefic the writetime update delay

    metze
    (This used to be commit 751ab2992afd13548af6e67a03d3ced566cb136f)

Change-Id: I8ff9fb8a8b66308f6d784351a0f43b5b234889d1
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>