On the svn-auth-x590 branch, don't re-allocate and copy the source data
buffer while parsing certificates, and don't keep a copy of the raw data
in the parsed result.

* subversion/libsvn_subr/x509.h
  (x509_cert): Remove 'raw' buffer for raw cert data.
  (svn_x509_parse_cert): Remove 'const' from input buffer to avoid
   having to cast away const in the implementation.

* subversion/libsvn_subr/x509parse.c
  (svn_x509_parse_cert): Don't copy input buffer and don't rely on
   the raw cert data buffer for parsing.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/svn-auth-x509@1603874 13f79535-47bb-0310-9956-ffa450edef68