Merge r382147 from trunk:

  APR_FILEPATH_NOTABOVEROOT was undefined with a left-hand NULL
  or empty path.  The SECUREROOTPATH and NOTABSOLUTE tests were
  sufficient for this application.  Adjusts for a bug in earlier
  versions of APR with this undefined value.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@390606 13f79535-47bb-0310-9956-ffa450edef68