Sleep for timestamps even if using commit times as timestamps.

Before r1463721, 'revert' did not sleep if using commit times, while
'checkout' and 'update' and 'switch' would sleep regardless.  r1463721 made
all of those operations omit the sleep if using commit times, but Philip and
Ben discussed and pointed out that the commit time could still be within the
timestamp resolution and so that could be unsafe.  Therefore we will sleep
anyway, in all of those operations, to be safe.

(The commit time could also be *after* the local time because of clock skew,
which adds the possibility that the sleep takes us *into* an unsafe time
period, but we're not trying to address that problem here.)

Found by: breser

* subversion/libsvn_client/revert.c
  (svn_client_revert2): Sleep regardless of use-commit-times.

* subversion/libsvn_client/switch.c
  (switch_internal): Sleep regardless of use-commit-times.

* subversion/libsvn_client/update.c
  (update_internal): Sleep regardless of use-commit-times. (Checkout also
  uses this code.)


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1464769 13f79535-47bb-0310-9956-ffa450edef68