[PATCH] Op-depth for copies - fixing lock_tests.py 40 - in progress

After Philip's great work I see just three op-depth failures remaining:

> FAIL: copy_tests.py 83: move a directory containing moved node
> FAIL: lock_tests.py 40: uncommitted svn:needs-lock add/cp not read-only
> FAIL: upgrade_tests.py 15: upgrade tree conflict data (f20->f21)

lock_tests.py 40 fails because my WC-to-WC copy code doesn't reset files
to read-write on disk when it copies them if svn:needs-lock was set on
the source, which the old code did; instead, it just copies exactly
what's there.

The attached patch is where I have got to today, attacking that from the
angle of abandoning my all-in-one approach now that Philip's made the
WC-to-WC code handle op-depth automatically. I try to extend that to
cover this case.

As it says in the log msg, it fixes lock_tests.py 40 but breaks
copy_tests.py 47. I haven't time today to go further with seeing why.

If anyone wants to look tonight, be my guest.

- Julian