On svn-auth-x509 branch, remove some unused/unnecessary fields.

* subversion/libsvn_subr/x509.h
  (x509_cert): Remove tbs, issuer_raw, subject_raw, pk_oid, v3_ext, ca_istrue,
    and max_pathlen members.

* subversion/libsvn_subr/x509parse.c
  (svn_x509_parse_cert): Remove the code to store the tbs and raw members of
    x509_cert struct.  These existed to allow some other app to be able to do
    its own parsing of the cert if it wanted something TropicSSL didn't
    provide, but we don't return the x509_cert struct so they're useless.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/svn-auth-x509@1607122 13f79535-47bb-0310-9956-ffa450edef68