On the svn-auth-x590 branch, tweak the name and declaration of the cert
parsing function.

* subversion/libsvn_subr/x509.h,
  subversion/libsvn_subr/x509parse.c
  (x509parse_crt): Rename to...
  (svn_x509_parse_cert): ... this. Pass in APR pools and start using them.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/svn-auth-x509@1603846 13f79535-47bb-0310-9956-ffa450edef68