Fix some sleep-for-timestamps code: avoid missing some cases where we need
to sleep -- especially error cases -- and avoid sleeping in some cases where
we don't need to.  Simplify the code by using a consistent pattern: make the
decision of whether to sleep at the lowest level possible (ideally in the WC
layer, but not yet), and do the sleep at the highest level possible
(immediately below the libsvn_client API).

Currently we sleep before releasing the WC write lock in some places, and
after releasing it in other places.  We should pick one and be consistent.

* subversion/libsvn_client/client.h
  (svn_client__update_internal,
   svn_client__checkout_internal,
   svn_client__switch_internal,
   svn_client__handle_externals): Document that the 'sleep' output is set
    even if the function returns an error, and don't let it be NULL.
  (svn_client__export_externals): Remove the unused and unneeded 'sleep'
    output parameter.

* subversion/libsvn_client/checkout.c
  (svn_client__checkout_internal): Rely on the caller to sleep even if we
    throw an error. Don't always sleep on success, only if we actually
    update the WC.
  (svn_client_checkout3): Handle the sleep here.

* subversion/libsvn_client/commit.c
  (svn_client_commit6): Sleep, if needed, even if there is an error during
    the post-commit 'bumping' of the WC.

* subversion/libsvn_client/copy.c
  (do_wc_to_wc_copies_with_write_lock,
   do_wc_to_wc_moves,
   repos_to_wc_copy_single): Return a flag instead of sleeping here. A
     multi-target repos-to-WC copy will now only sleep once, not once per
     target.
  (do_wc_to_wc_copies,
   repos_to_wc_copy_locked,
   repos_to_wc_copy,
   try_copy): Pass the flag through.
  (svn_client_copy6,
   svn_client_move7): Handle the sleep here.

* subversion/libsvn_client/export.c
  (export_directory): Remove the unneeded 'sleep' variable.

* subversion/libsvn_client/externals.c
  (svn_client__export_externals): Remove the unused and unneeded 'sleep'
    output parameter.

* subversion/libsvn_client/revert.c
  (svn_client_revert2): Sleep even when returning an error. It was missing
    the case where, after reverting at least one target, a subsequent target
    fails.

* subversion/libsvn_client/switch.c
  (switch_internal): Rely on the caller to sleep even if we throw an error.
    It missed the case where externals handling fails. Don't require a sleep
    if we're using commit times as the WC timestamps.
  (svn_client_switch3): Handle the sleep here.

* subversion/libsvn_client/update.c
  (update_internal): Rely on the caller to sleep even if we throw an error.
    It missed the case where externals handling fails. Don't require a sleep
    if we're using commit times as the WC timestamps. This is also used by
    checkout, so these changes affect checkout as well.
  (svn_client_update4): Handle the sleep here in all cases. It missed the
    case where, after updating at least one target, a subsequent target
    fails.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1463721 13f79535-47bb-0310-9956-ffa450edef68