On 'svn-auth-x509' branch: Don't dereference pointers that might be outside the
length of the buffer.

* subversion/libsvn_subr/x509parse.c
  (x509_get_name, x509_get_date, x509_get_sig, x509_get_uid): Don't retrieve
    the tag from the pointer before checking the length, which asn1_get_tag()
    does for us.  It also compares the tag to the one we ask for, so where
    we want to store the tag, store it explicilty rather than from the tag.

Found by: philip


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/svn-auth-x509@1635357 13f79535-47bb-0310-9956-ffa450edef68