Merge r1580650 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1580626@1580652 13f79535-47bb-0310-9956-ffa450edef68
* subversion/tests/libsvn_wc/op-depth-test.c
  (SVN_VA_NULL): Define this macro here, to avoid further backport problems.



git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1580626@1580661 13f79535-47bb-0310-9956-ffa450edef68