Within libsvn_repos get_log functionality, pass the list of wanted revprops
around as an array of svn_string_t* instead of const char*.  The added length
info allows for more effient functions to be used.  Do that.

* subversion/libsvn_repos/log.c
  (fill_log_entry): try an optimistic match between received and requested
                    revprops; adapt to using svn_string_t *
  (svn_repos_get_logs4): copy & convert the incoming array


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1483570 13f79535-47bb-0310-9956-ffa450edef68