On svn-auth-x509 branch, use SVN and APR time formats/functions.

* subversion/libsvn_subr/x509.h
  (x509_time): Remove
  (x509_cert): Use apr_time_t instead of x509_time.

* subversion/libsvn_subr/x509parse.c
  (x509_utc_to_apr_time): New function
  (x509_get_dates): Update to use x509_utc_to_apr_time().
  (svn_x509_parse_cert): Use svn_time_to_human_cstring() to format dates.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/svn-auth-x509@1605934 13f79535-47bb-0310-9956-ffa450edef68