Resolve an issue found while looking into a problem reported on #svn: a
copy between two different working copies just failed, because it tried to
access unneeded working copy state.

* subversion/libsvn_wc/wc_db.c
  (cross_db_copy): Don't try to read pristine property values for not present
    nodes, as that will result in an error.

* subversion/tests/cmdline/copy_tests.py
  (ext_wc_copy_deleted): New test.
  (test_list): Add test.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1589184 13f79535-47bb-0310-9956-ffa450edef68