Revert the calls of the renamed svn_wc__get_wcroot back to svn_wc
__get_wc_root, so the fix compiles against SVN 1.7. (The function was 
renamed in r1427830.)

* subversion/libsvn_client/copy.c
  (do_wc_to_wc_moves): Fixed function name to svn_wc__get_wc_root.

Approved by: rhuijben


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.7.x-r1551579@1557072 13f79535-47bb-0310-9956-ffa450edef68