* Correctly terminate string in SSL client certificate extensions

  parsing by ensuring that it always has a \0 at the end.

PR: PR 44073
Submitted by: yl <yl bee-ware.net>
Reviewed by: rpluem, jorton, trawick


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@604403 13f79535-47bb-0310-9956-ffa450edef68